Image display device

ABSTRACT

The present invention provides an image display device which detects projection region suitable for performing a display of an image and displays an image on the detected projection region. The present invention provides an image display device which displays an image on a projection surface by projecting light on the projection surface. The image display device includes an aptitude detection part which detects an aptitude as the projection surface, and a projection control part which controls projection light such that the an image to be displayed on the projection surface falls within a predetermined projection region in response to a detection result by the aptitude detection part. For example, the image display device further includes an aptitude value arithmetic operation part which recognizes the projection area as a mass of a plurality of divided regions and detects aptitude values of projection surfaces of the respective divided regions, a projection region determining part which selects one or more divided regions out of the plurality of divided regions as the projection regions based on the aptitude values, and an image processing part which controls projection light such that an image to be projected on the projection surface falls within one or more projection regions.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation-in-Part of InternationalApplication PCT/JP2007/053605 filed on Feb. 27, 2007, which claims thebenefits of Japanese Patent Application No. 2006-054047 filed on Feb.28, 2006 and Japanese Patent Application No. 2006-064799 filed on Mar.9, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image display device such as aprojector for displaying an image on a projection surface such as ascreen.

2. Description of the Related Art

The image display device such as a projector is provided for projectingan image such as a still image or an animated image of an OHP or a slideon a projection surface such as a screen.

Recently, in making the presentation to a plurality of people concerned,a document stored in a computer device is projected on an image displaydevice, and the explanation or the like is made using an image displayedon the projection surface (see JP-A-2003-280091 (patent document 1), forexample).

In displaying an image on the projection surface using such an imagedisplay device, when unevenness exists on the projection surface or anobstacle exists on the projection surface or in the midst of an opticalpath of a projection light, there arises a drawback that a projectedimage is distorted or a shadow of the obstacle is displayed on theprojection surface. Accordingly, several methods have been proposedconventionally for preventing the occurrence of such drawback.

For example, there has been known one conventional image display devicewhich detects whether or not a projection light is projected in theoblique direction relative to a screen. When the projecting direction isoblique relative to the screen, a trapezoidal distortion generated dueto the presence of the oblique projecting direction is automaticallycorrected (see JP-A-4-355740 (patent document 2), for example).

Further, there has been also known an image display device whichradiates detection waves such as infrared rays to a screen, and detectsreflection waves reflected from a screen side thus detecting thepresence or non-presence of an obstacle. Then, when the obstacle isdetected, a quantity of projection light is reduced or the projection isinterrupted by taking a case that the obstacle is a human intoconsideration (see JP-A-2004-70298 (patent document 3), for example).

SUMMARY OF THE INVENTION

However, none of these conventional image display devices can preventthe distortion of image generated by unevenness which exists partiallyon the surface of the screen. Further, the image display devicesdisclosed in patent document 1 and patent document 2 cannot detect anobstacle present in the midst of the optical path of the projectionlight and hence, these image display devices cannot prevent the shadowof the obstacle from being displayed. Further, although the imagedisplay device disclosed in patent document 3 can detect the obstacle inthe midst of the optical path, a quantity of projection light isdecreased or the projection is interrupted when the obstacle is detectedand hence, the image is no more displayed or it is difficult for aviewer to watch an image due to shortage of light quantity.

The present invention has been made to overcome such drawbacks and it isan object of the present invention to provide an image display devicewhich detects projection region suitable for performing a display of animage and displays an image on the detected projection region.

To overcome the above-mentioned drawbacks, according to a first aspectof the present invention, there is provided an image display device forprojecting light on a projection surface to display an image on theprojection surface, wherein the image display device includes: anaptitude detection part which detects an aptitude as the projectionsurface; and a projection control unit which controls the projectionlight to allow the image to be displayed on the projection surface tofall within a predetermined projection region in response to a result ofdetection by the aptitude detection part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an image display device of a firstembodiment;

FIG. 2 is a perspective view showing a projection area of the imagedisplay device shown in FIG. 1;

FIG. 3A is a front view showing a shape of the projection area anddivided regions;

FIG. 3B is an explanatory view for explaining a center position and areflection point in the divided region;

FIG. 4 is an explanatory view for explaining a function of a controllerof the image display device shown in FIG. 1;

FIG. 5A and FIG. 5B are explanatory views for explaining processing ofan obstacle detection part in an arithmetic processing part ofcontroller;

FIG. 6 is an explanatory view for explaining the processing of theobstacle detection part in the arithmetic processing part of thecontroller;

FIG. 7A is an evaluation-use distance table used for obtaining anaptitude value;

FIG. 7B is a spaced-apart distance table used for obtaining the aptitudevalue;

FIG. 8 is an explanatory view for explaining one example of aptitudevalues obtained with respect to the respective divided regions withrespect to the first embodiment;

FIG. 9A to FIG. 9C are explanatory views for explaining processing of aprojection region determination part;

FIG. 10A to FIG. 10C are explanatory views for explaining the processingof the projection region determination part;

FIG. 11 is an explanatory view for explaining the processing of theprojection region determination part;

FIG. 12 is a flowchart showing the manner of operation of the imagedisplay device of the first embodiment;

FIG. 13 is a flowchart showing processing of the obstacle detectionpart;

FIG. 14 is a flowchart showing processing for determining whether or notone remaining evaluation position is positioned on one straight line outof processing of the obstacle detection part;

FIG. 15 is a flowchart showing processing of an aptitude valuearithmetic operation part;

FIG. 16 is a flowchart showing processing of a projection regiondetermination part;

FIG. 17A to FIG. 17C are explanatory views for explaining specificdisplay states;

FIG. 18 is a plan view showing the schematic constitution of an imagedisplay device of a second embodiment;

FIG. 19 is an explanatory view for explaining a function of a controllerof the image display device shown in FIG. 18;

FIG. 20 is a luminosity table used in obtaining aptitude values;

FIG. 21 is an explanatory view for explaining one example of aptitudevalues obtained with respect to the respective divided regions withrespect to the second embodiment;

FIG. 22 is a flowchart showing the manner of operation of the imagedisplay device of the second embodiment;

FIG. 23 is a flowchart showing processing of an aptitude valuearithmetic operation part;

FIG. 24 is a flowchart showing processing for determining whether or notone remaining evaluation position is positioned on one straight line outof processing of the obstacle detection part;

FIG. 25 is a side view of a desktop-type image display device;

FIG. 26 is a side view of another desktop-type image display device;

FIG. 27 is a side view of still another ceiling-installing-type imagedisplay device;

FIG. 28 is a perspective view of appearance of an image display deviceof a third embodiment of the present invention;

FIG. 29 is a side view showing the relationship between a projectionangle θs of a projection light projected from a projection portion andan inclination angle θd made of an acute angle in a projection region;

FIG. 30 is a side view showing the relationship between the projectionangle θs of a projection light projected from a projection portion andthe inclination angle θd in the projection region;

FIG. 31 is a block diagram of a signal processing system of the imagedisplay device shown in FIG. 28;

FIG. 32 is a flowchart of processing for projecting operation functioninformation;

FIG. 33 is a flowchart of processing for executing adjustment of animage size and adjustment of a projection position;

FIG. 34A and FIG. 34B are views for explaining a state in which theadjustment of the image size is performed;

FIG. 35 is a view for explaining a state in which the projectionposition is shifted;

FIG. 36 is a view showing the arrangement of optical parts for realizingthe change of the image size and the shifting of the projectionposition;

FIG. 37 is a flowchart of processing for executing the adjustment of theimage size and the adjustment of the projection position based onwhether or not a photo detector receives a projection light;

FIG. 38 is a flowchart for executing menu projection processing;

FIG. 39 is a view showing a projection example of operation functioninformation;

FIG. 40 is a view showing a menu image and a projection example ofinverted projection object information in the menu image;

FIG. 41 is a view showing a projection example of operation functioninformation projected together with the menu image shown in FIG. 40;

FIG. 42 is a view showing a menu image and a projection example ofinverted projection object information in the menu image;

FIG. 43 is a flowchart of processing executed after the selection of aninverted object in menu projection processing shown in FIG. 38;

FIG. 44 is a view showing a projection example of an additional menuimage;

FIG. 45 is a flowchart for explaining an image projection processing forsetting a projection position of an image, an image size, brightness andthe like;

FIG. 46 is a view showing a projection example of a setting image usedfor manually changing an image size;

FIG. 47 is a view showing a projection example of operation functioninformation projected together with the setting image shown in FIG. 46;

FIG. 48 is a view showing a projection example of a setting image;

FIG. 49 is a view showing an embodiment of an image display deviceprovided with a bearing mechanism for changing a height of a projectionportion;

FIG. 50 is a view showing an embodiment of an image display deviceprovided with a mechanism for accommodating a screen;

FIG. 51 is a view showing an embodiment of an image display deviceprovided with a stylizing member for preventing an overturn of the imagedisplay device together with a mechanism for accommodating a screen;

FIG. 52 is a view showing an embodiment of an image display deviceprovided with a stylizing member for preventing an overturn of the imagedisplay device on a pedestal;

FIG. 53 is a view showing an embodiment of an image display deviceimparting a function of screen to a pedestal; and

FIG. 54 is a view showing an embodiment of an image display deviceprovided with a foldable screen on a pedestal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Hereinafter, a projector according to an embodiment of an image displaydevice is explained in detail in conjunction with drawings. With respectto symbols used in the respective drawings, parts having an identicalfunction are given the same symbols.

As shown in FIG. 1, a projector 10 includes a light source unit 12mounted in a projector body 11 thereof and a projection lens part 13mounted on a front surface of the projector body 11. The light sourceunit 12 includes a light source 12 a for projecting a projecting light Lto display an image (see FIG. 2) and a light source control part 12 bfor controlling the light source 12 a in response to signals from animage processing part 27 described later. Further, the projection lenspart 13 includes a projection lens 14, and the projecting light L isprojected on a screen S or the like using the projection lens 14.

As shown in FIG. 2, a shape of an area on which an image can beprojected using the projection light L, that is, a shape of a projectionarea A is a laterally-elongated rectangular shape. Further, theprojection area A is, by a controller 20 (see FIG. 4) described later,recognized as amass of a plurality of divided regions B as shown in FIG.3A. To be more specific, the projection area A is recognized as a massof the sixteen divided regions B in total extending vertically in fourrows and laterally in four columns. Each divided region B has alaterally-elongated shape similar to the shape of the projection area A.In identifying an individual divided region B, the explanation is madeby adding a suffix indicative of a position of the divided region B. Forexample, “divided region B21” is a divided region B positioned at thesecond column from the left and at the first row from above with respectto the projection light L projected toward the screen S from the lightsource 12 a of the projector 10.

Here, the projection area A actually means a space through which theprojection light L from the light source 12 a advances. However, here,assuming that a plane orthogonal to a projecting direction X of theprojection light L is provided, a shape of a projection range of theprojection light L projected on the plane becomes a shape of theprojection area A (see FIG. 2). Further, the divided region B, aprojection candidate region C and a projection region D described lateralso mean predetermined spaces through which the projection light L fromthe light source 12 a advances. Here, in the same manner as theprojection area A, a shape of each region such as the divided region Bprojected on a plane orthogonal to the projecting direction X of theprojection light L is rendered as the shape of the divided region B.

Further, as shown in FIG. 1, the projector 10 includes a zooming unit 15and a focusing unit 16 provided to the projection lens part 13, a lightquantity adjuster 17 mounted in the projector body 11, a sensor unit 18mounted on a front surface of the projector body 11, an ON-OFF switchand a power source unit (neither of them shown in the drawing) of theprojector 10. Further, the projector 10 mounts the controller 20 foroperation control in the projector body 11. Here, lines for supplyingelectric power to respective devices and the like are omitted.

The zooming unit 15 is provided for enlarging or shrinking an image tobe projected on the screen S and includes a zooming mechanism 15 a and azooming motor 15 b for operating the zooming mechanism 15 a (see FIG.4). Further, the focusing unit 16 includes a focus adjusting mechanism16 a which adopts a so-called helicoid mechanism and a focusing motor 16b for operating the focus adjusting mechanism 16 a (see FIG. 4). Zoomingand focus adjusting of the projection lens 14 are performed by operatingthe zooming mechanism 15 a and the focus adjusting mechanism 16 a usingthese motors 15 b, 16 b. Here, these mechanisms are known mechanisms andhence, the detailed explanation of these mechanisms is omitted.

The light quantity adjuster 17 is a voltage-variable light quantityadjuster and adjusts quantity of light by adjusting a voltage ofelectric power supplied to the light source 12 a. With the provision ofthe light quantity adjuster 17, an image having a suitable brightnesscan be displayed on the screen S. Here, the light adjusting method isnot limited to the voltage-variable light adjusting method, and variousother methods including a method which uses a stop or a filter may beused.

The sensor unit 18 includes a plurality of distance sensors 19 formeasuring distances from the projector 10. To be more specific, thesensor unit 18 includes sixteen distance sensors 19 which is the same asthe number of the divided regions B. Each distance sensor 19 includes aradiating part 19 a for radiating an infrared ray (detection waves) Irtoward the inside of the projection area A of the projector 10 and areflection wave detecting part 19 b for detecting a reflection wave ofthe infrared ray Ir. Further, the sensor unit 18 includes a reflectionpoint distance arithmetic operation part 18 a (see FIG. 4) for obtaininga distance from the distance sensor 19 to a reflection point Pr of theinfrared ray Ir (see FIG. 3B) based on detected information.

As shown in FIG. 3A, the radiating part 19 a of each distance sensor 19radiates an infrared ray Ir toward the center Bc of the correspondingdivided region B. Accordingly, when the screen S is arranged in theprojecting direction of the projection light L, the infrared ray Irradiated from the distance sensor 19 is reflected on a surface of thescreen S at a position of the center Bc of the corresponding dividedregion B. Then, the reflection wave of the infrared ray Ir (hereinafter, referred to as reflected infrared ray) Rr is detected by thereflection wave detecting part 19 b of the distance sensor 19.

Here, a position of the projection lens 14 for projecting the projectionlight L differs from positions where the radiating parts 19 a of thedistance sensors 19 which radiate the infrared ray Ir are positioned.Accordingly, as shown in FIG. 3B, there is a possibility that theposition of the actual reflection point Pr of the infrared ray Ir isdisplaced from the position of the center Bc of the correspondingdivided region B. However, the distance between the projection lens 14and the distance sensor 19 is smaller than the distance from theprojector 10 to the reflection point Pr and hence, a displacementquantity of the reflection point Pr from the center Bc is slight.Accordingly, in this embodiment, the radiation direction of the infraredray Ir of each distance sensor 19 is explained as the direction of theinfrared ray Ir toward the position of the center Bc of thecorresponding divided region B.

The reflection point distance arithmetic operation part 18 a of thesensor unit 18 (see FIG. 4) obtains a distance from the distance sensor19 to the reflection point Pr based on the radiation direction of theinfrared ray Ir and an incident direction of the reflected infrared rayRr from the reflection point Pr in each distance sensor 19. Further, thereflection point distance arithmetic operation part 18 a also obtainsthe position of each reflection point Pr with respect to the position ofthe distance sensor 19 based on the obtained distance to the reflectionpoint Pr and the radiation direction of the infrared ray Ir and/or theincident direction of the reflected infrared ray Rr. The distance fromthe distance sensor 19 to the reflection point Pr and the position ofthe reflection point Pr with respect to the distance sensor 19 arestored in a center position memory part 42 of a memory 20 b describedlater via a controller 20. The distance from the distance sensor 19 tothe reflection point Pr can be obtained using the principle oftriangulation or the like provided that the radiation direction of theinfrared ray Ir and the incident direction of the reflected infrared rayRr from the reflection point Pr are as known. Accordingly, theexplanation of the method of obtaining the distance from the distancesensor 19 to the reflection point Pr is omitted here.

Here, as described above, as shown in FIG. 3B, the actual position ofthe reflection point Pr is not always positioned on the center Bc of thedivided region B. Accordingly, a correction may be made with respect tothe position of the actual reflection point Pr. For example, when theposition of the reflection point on the assumption that the reflectionpoint is positioned at the center Bc of the divided region B is obtainable by the correction, the corrected reflection point position obtainedby the correction may be stored in the center position memory part 42.

Next, the controller 20 is explained.

As shown in FIG. 4, the controller 20 includes an arithmetic operationprocessing part 20 a which performs various processing and the memory 20b which stores various data therein.

The arithmetic operation processing part 20 a includes a divided regionrecognizing part 21 for recognizing the projection area A as a mass of aplurality of divided regions B, an evaluation position arithmeticoperation part 22 for obtaining an evaluation position Pe of eachdivided region B (see FIG. 5) based on the position of the reflectionpoint measured by the distance sensor 19, an obstacle detecting part 23for detecting an obstacle W or the unevenness present in each dividedregion B, an aptitude value arithmetic operation part 24 for obtainingan aptitude value R of each divided region B as a projecting surface, acandidate region determining part 25 for determining a projectioncandidate region C out of the divided regions B, a projection regiondetermining part 26 for selecting a projection region D out of theprojection candidate regions C, an image processing part 27 forperforming image processing to display an image in the selectedprojection region D, a focusing control part 28 for controlling thefocusing motor 16 b for the projection lens 14 and a light quantitycontrol part 29 for controlling the light quantity adjuster of the lightsource. The aptitude value arithmetic operation part 24 is provided fordetecting an aptitude of the projecting surface and corresponds to oneexample of an aptitude detecting part. The candidate region determiningpart 25 and the projection region determining part 26 are provided forselecting a projection region based on the detection result obtained bythe aptitude value arithmetic operation part 24 and corresponds to oneexample of a region selection part. The image processing part 27 isprovided for controlling a projection light so that an image displayedon the projecting surface falls within a predetermined projection regionbased on the detection result obtained by the aptitude value arithmeticoperation part 24, and corresponds to one example of the projectingcontrol part.

Further, the memory 20 b includes a dividing line memory part 41 forstoring information on dividing lines which divide the projection area Ainto a plurality of divided regions B, the center position memory part42 for storing positions of reflection points Pr measured by therespective distance sensors 19, an evaluation position memory part 43for storing the evaluation positions Pe obtained with respect to therespective divided regions B, an evaluation distance memory part 44 forstoring distances Le from the respective divided regions B to theevaluation positions Pe, an obstacle information memory part 45 forstoring information on whether or not an obstacle W or the unevenness ispresent in the respective divided regions B, an aptitude value memorypart 46 for storing aptitude values R obtained with respect to therespective divided regions B, a candidate region memory part 47 forstoring information whether or not the respective divided regions B aredetermined as the projection candidate regions C, a projection regionmemory part 48 for storing information whether or not each projectingcandidate region C is selected as a projection region D, and a basicinformation memory part 49 for storing data and tables to be used in anarithmetic operation executed by the arithmetic operation processingpart 20 a.

The controller 20 recognizes, in the divided region recognizing part 21,as explained previously, the projection area A as a mass of a pluralityof divided regions B based on division information stored in thedividing line memory part 41. As shown in FIG. 3A, the projection area Ais divided into regions extending vertically in four rows and laterallyin four columns and is recognized as a mass of the sixteen dividedregions B in total. Accordingly, when the projection light L isprojected on a plane orthogonal to a projecting direction X of theprojection light L, the centers Bc of the divided regions B arrangedvertically in the projection area A are positioned on one straight lineand, in the same manner, the centers Bc of the divided regions Barranged laterally are also positioned on one straight line. Here, thedivision information stored in the dividing line memory part 41 is, forexample, position information of dividing lines in a matrix array whichdivides the projection area A.

The evaluation position arithmetic operation part 22 obtains theevaluation position Pe of each divided region B based on the position ofthe reflection point Pr of each divided region B measured by eachdistance sensor 19. The position of the reflection point Pr measured bythe distance sensor 19 is stored in the center position memory part 42as a relative position with respect to the position of the distancesensor 19. The stored position of the reflection point Pr may bedirectly used as the evaluation position. In this case, the evaluationposition arithmetic operation part 22 is unnecessary. In thisembodiment, with the use of the evaluation position arithmetic operationpart 22, the position of each reflection point Pr is converted into theposition which is expressed as the relative position with respect to theposition of the projection lens 14 and the converted position is set asthe evaluation position Pe of each divided region B. In this manner, bysetting the common standard for determining the respective evaluationpositions Pe, the arithmetic operation executed thereafter isfacilitated. Here, various positions such as the positions of therespective distance sensors 19 described later are positions relative tothe position of the projection lens 14 unless otherwise specified.

In the evaluation position arithmetic operation part 22, first of all, adivided region B to be subjected to the arithmetic operation isselected, and the position of the reflection point Pr corresponding tothe selected divided region B is read from the center position memorypart 42. Then, the position of the distance sensor 19 which measures theposition of the reflection point Pr of the selected divided region B andthe position of the projection lens 14 are read from the basicinformation memory part 49 of the memory 20 b. Based on these positions,the evaluation positions Pe of the respective divided regions B areobtained. The obtained evaluation positions Pe are stored in theevaluation position memory part 43 as the evaluation positions Pe of thecorresponding divided regions B. In the evaluation position arithmeticoperation part 22, the distances from the projection lens 14 to therespective evaluation positions Pe are obtained. Here, the obtaineddistances are stored in the evaluation distance memory part 44 as theevaluation distances Le to the corresponding divided regions B. Suchprocessing is performed with respect to all the divided regions B. Here,the evaluation positions Pe and the evaluation distances Le can beobtained using the principle of triangulation or the like provided thatthe positions of the reflection point Pr, the positions of the distancesensor 19 and the positions of the projection lens 14 are known.Accordingly, the method for obtaining the evaluation positions Pe andthe evaluation distances Le is omitted here.

The obstacle detecting part 23 executes processing for detecting anobstacle W or the unevenness present in each divided region B (see S03in FIG. 12).

As described in a flowchart shown in FIG. 13, the obstacle detectingpart 23 recognizes the projection area A as a plurality of dividedregions B (S03-1) and selects three divided regions B from therecognized divided regions B (S03-2). Although various selection mannersare considered, in this embodiment, three divided regions B arrangedvertically or laterally are selected. Next, the evaluation positions Peof the three selected divided regions B are read from the evaluationposition memory part 43 (S03-3). Then, it is determined whether or notthe three read evaluation positions Pe are positioned on one straightline (that is, on one plane) (S03-4) and the determination result isstored in the obstacle information memory part 45. Thereafter, it isdetermined whether or not there exists a non-selected divided region B(S03-5). When there exists such a non-selected divided region B, theprocessing returns to the step (S03-2) for selecting three dividedregions B out of the non-selected divided regions B, and the processingis repeated until the evaluation is finished with respect to all thedivided regions B (S03-5). Here, until the evaluation is made withrespect to all the divided regions B, the same divided region B may beselected plural times or the same divided region may not be repeatedlyselected. Further, in respective flowcharts used in this embodimentincluding the flowchart shown in FIG. 13, although flows of processingsuch as detection processing, the determination processing and the likeare explained, processing of storing information in the memory parts orthe like is omitted.

Here, as explained above, when the projection light L is projected on aplane orthogonal to the projecting direction X, the positions of thecenters Bc of the divided regions B arranged vertically or the positionsof the centers Bc of the divided regions B arranged laterally arepositioned on one straight line. In this embodiment, the positions ofthe reflection points Pr positioned at the centers Bc of the respectivedivided regions Bare used as the evaluation positions Pe of therespective divided regions B. Accordingly, when the screen S on whichthe projection light L is projected is a plane, the three evaluationpositions Pe are positioned on one straight line and, when there existsan obstacle W (see FIG. 5) or the unevenness, the three evaluationpositions Pe are not positioned on one straight line. As can beunderstood from this explanation, the determination whether or not threeevaluation positions Pe are positioned on one straight line is alsoexpressed as the determination whether or not three evaluation positionsPe are arranged to and fro in relation to the projection X and hence,this technique is suitable as a projecting direction determiningtechnique for detecting an obstacle or the unevenness.

As a method of determining whether or not three evaluation positions Peare positioned on one straight line, various methods are considered.Here, a basic determination method is explained by taking a case inwhich three divided regions B11, B12, B13 (see FIG. 3A) positioned onthe first column from the left of the projection area A are selected asan example. As shown in FIG. 5A, for example, coordinates (x2, y2) ofthe evaluation position Pe2 of the divided region B12 positioned at thecenter of three evaluation positions Pe are, as expressed by thefollowing formula 2, specified by the distance L2 from the position ofthe corresponding distance sensor 19 to the evaluation position Pe2 andan angle θ2 made by the direction of the evaluation position Pc2 and theprojecting direction X. Here, coordinates of evaluation positions Pe1,Pe3 of other divided regions B11, B13 are also specified using thefollowing formulae 1 and 3.x1=L1×cos θ1, y1=L1×sin θ1  (formula 1)x2=L2×cos θ2, y2=L2×sin θ2  (formula 2)x3=L3×cos θ3, y3=L3×sin θ3  (formula 3)

Two evaluation positions are selected from three evaluation positionsPc1, Pc2, Pc3 specified in the above-described manner, and it isdetermined whether or not remaining one evaluation position ispositioned on a straight line formed by joining two selected evaluationpositions. Due to such a method, it is determined whether or not threeevaluation positions Pe are positioned on the same straight line. Forexample, as shown in FIG. 5B, when an obstacle W exists in the dividedregion B12, the evaluation position Pe2 of the divided region B12 isdetermined to be positioned frontward from a line segment obtained byjoining other evaluation positions Pe1, Pe3 and hence, it is determinedthat three evaluation positions Pe1, Pe2, Pe3 are not positioned on onestraight line.

In the projector 10 of this embodiment, the determination whether or notthree evaluation positions Pe1, Pe2, Pe3 are positioned on one straightline is made using the following method. As described in the flowchartshown in FIG. 14, first of all, extending directions of three linesegments in total obtained by joining the selected two evaluationpositions out of three evaluation positions Pe1, Pe2, Pe3 are obtained(S03-4-1). To be more specific, as shown in FIG. 6, a long line segmentFL which is obtained by joining the evaluation positions Pe1, Pe3positioned at both ends out of three evaluation positions Pe1, Pe2, Pe3and two short line segments FS1, FS2 which are obtained by joining theevaluation position Pe2 positioned at the center and the respectiveremaining evaluation positions Pe1 and Pe3 are specified thus obtainingthe position and the extending directions of the respective linesegments FL, FS1, FS2. Next, the relationships among the extendingdirections of the respective line segments FL, FS1, FS2 and theprojecting direction X of the projection light L are determined(S03-4-2, 4, 6, 7). When three divided regions B arranged vertically areselected as in the case of the example of this embodiment, it isdetermined whether or not the extending directions of the respectiveline segments EL, FS1, FS2 are parallel to a first reference line Vorthogonal to the projecting direction X. When three divided regionsarranged laterally are selected, it is determined whether or not theextending directions of the respective line segments FL, FS1, FS2 areparallel to a second reference line H orthogonal to the projectingdirection X. Here, a state in which a first reference line orthogonal tothe projecting direction X is used as the first reference line V, and asecond reference line orthogonal to the projecting direction X is usedas the second reference line H is shown. However, the reference line maynot always be necessary to be vertical or horizontal.

When all the line segments EL, FS1, FS2 are parallel to the firstreference line V (S03-4-2) as a result of the determination, a detectionresult that three evaluation positions Pc1, Pc2, Pc3 are positioned onone straight line (one plane) is obtained. When there exists no obstacleor unevenness in the selected divided region B, such a result isobtained. When the detection result is obtained, a spaced-apart distanceG (see FIG. 6) from the respective three evaluation positions Pe1, Pe2,Pe3 to a line segment parallel to the first reference line V is obtainedand stored in the obstacle information memory part 45. However, when allthe line segments are parallel to the first reference line V, thespaced-apart distance G from the respective evaluation positions Pe1,Pe2, Pe3 to the line segment parallel to the first reference line V isobtained as 0 (S03-4-3) and this information is stored in the obstacleinformation memory part 45.

Further, when the long line segment FL and one short line segment FS1(FS2) are parallel to the first reference line V while the other shortline segment FS2 (FS1) is not parallel to the first reference line V(S03-4-4), a determination result that three evaluation positions Pe1,Pe2, Pe3 are not positioned on one straight line is obtained. Forexample, as shown in FIG. 6, when an obstacle W exists in the dividedregion B12 positioned at the center, such a result is obtained. In thiscase, the spaced-apart distance G is 0 with respect to the evaluationpositions Pe1, Pe3. Then, the spaced-apart distance G from theevaluation position Pe2 positioned at the center to the line segment FLparallel to the first reference line V is obtained (S03-4-5) and thespaced-apart distance G is stored in the obstacle information memorypart 45.

Further, when the long line segment FL is parallel to thefirst-reference line V while the two short line segments FS1, FS2 arenot parallel to the first reference line V (S03-4-6), a detection resultthat three evaluation positions Pe1, Pe2, Pe3 are not positioned on onestraight line is obtained. When an obstacle W exists in the dividedregion B12 positioned at the center, such a result is obtained (see FIG.6). In this case, the spaced-apart distance G is 0 with respect to theevaluation positions Pe1, Pe3. Here, the spaced-apart distance G fromthe evaluation position Pe2 at the center to the line segment FLparallel to the first reference line V is obtained (S03-4-5) and isstored in the obstacle information memory part 45. However, when oneshort line segment is not parallel to the first reference line V,usually, the other short line segment is also not parallel to the firstreference line V. Accordingly, the determination is made with respect toeither one of the case in which one short line segment is not parallelto the first reference line V and the case in which both short linesegments are not parallel to the first reference line V withoutdistinguishing one case from another.

Further, when one short line segment FS1 (FS2) is parallel to the firstreference line V while the other short line segment FS2 (FS1) and thelong line segment FL are not parallel to the first reference line V(S03-4-7), a determination result that three evaluation positions Pe1,Pe2, Pe3 are not positioned on one straight line is obtained. Forexample, when an obstacle or the unevenness exists in the divided regionB13 and the short line segment FS2 is not parallel to the firstreference line V, such a result is obtained. In this case, thespaced-apart distance G is 0 with respect to the evaluation positionsPc1, Pc2. Then, the spaced-apart distance G from the evaluation positionPe3 to the line segment FS1 parallel to the first reference line V isobtained (S03-4-8) and is stored in the obstacle information memory part45.

Further, when none of line segments FL, FS1, FS2 is parallel to thefirst reference line V, a determination result that three evaluationpositions Pe1, Pe2, Pe3 are not positioned on one straight line isobtained. For example, when there exists an obstacle or the unevennesswhich strides over all the divided regions B11, B12, B13, such adetection result is obtained. In this case, a detection result that thespaced-apart distance G between the first reference line V and theparallel line segment is not measurable with respect to all evaluationpositions Pe1, Pe2, Pe3, (S03-4-9) is required, and information that thespaced-apart distance G is not measurable with respect to all evaluationpositions Pe1, Pe2, Pe3 is stored in the obstacle information memorypart 45.

Here, in determining whether or not three evaluation positions Pe arepositioned on one straight line, error is taken into consideration whennecessary. As a determination method which takes the error intoconsideration, various methods are considered. For example, it may bepossible to adopt a method which establishes, in determining whether ornot the respective line segments FL, FS1, FS2 are parallel to areference line such as the first reference line V, an allowable range inthe determination criteria. To explain the method specifically, evenwhen angles made between the respective line segments FL, FS1, FS2 andthe reference line are not accurately 0°, it is determined that therespective line segments FL, FS1, FS2 are parallel to the reference lineprovided that the angle assumes a value which falls within ±15°.

The aptitude value arithmetic part 24 detects aptitude values R of therespective divided regions B based on the stored data in the evaluationdistance memory part 44 and the obstacle information memory part 45. Inthe evaluation distance memory part 44, distances (evaluation distances)Le from the projection lens 14 to the respective evaluation positions Peare stored. In the obstacle information memory part 45, the spaced-apartdistances G between the reference line V, H (see FIG. 6) and theparallel line segments are stored with respect to the evaluationpositions Pe of the respective divided regions B. When the spaced-apartdistance G cannot be measured, information that the spaced-apartdistance G is not measurable is stored.

Further, the aptitude value arithmetic operation part 24 uses, inobtaining the aptitude value R, an evaluation distance table T1 and aspaced-apart distance table T2 stored in the basic information memorypart 49 in the memory 20 b. The evaluation distance table T1 is a tableshown in FIG. 7A for converting the evaluation distances Le obtainedwith respect to the respective divided regions B into numerical valuesR1 for the aptitude value arithmetic operation. Here, in the table T1,“slightly spaced-apart” implies that the projecting distance is half ofor more than half of a specified projecting distance and less than thespecified projecting distance, and “largely spaced-apart” implies thatthe projecting distance is the specified projecting distance or more.The spaced-apart distance table T2 is a table shown in FIG. 7B forconverting the spaced-apart distances G stored in the obstacleinformation memory part 45 into numerical values R2 for the aptitudevalue R arithmetic operation. Here, in the table T2, “slightlyspaced-apart” implies that the spaced-apart distances G is 5 mm or moreand less than 20 mm, and “largely spaced-apart” implies that thespaced-apart distances G is 20 mm or more.

As described in a flowchart shown in FIG. 15, first of all, the aptitudevalue arithmetic operation part 24 selects a divided region B for whichthe aptitude value is calculated, and an evaluation value Le of theselected divided region B is read from the evaluation distance memorypart 44 (S04-1). Then, the numerical value R1 for calculating theaptitude value is obtained by reference to the evaluation distance tableT1 shown in FIG. 7A with the read evaluation distance Le (S04-2). Forexample, when the evaluation distance Le is the specified projectingdistance or more, the numerical value R1 is 2 points. Next, from theobstacle information memory part 45, the spaced-apart distance G withrespect to the evaluation position Pe of the corresponding dividedregion B is read (S04-3). Then, a numerical value R2 for the aptitudevalue arithmetic operation is obtained by reference to the spaced-apartdistance table T2 shown in FIG. 7B with the read spaced-apart distance G(S04-4). For example, when the spaced-apart distance G is 10 mm, thenumerical value R2 is 3 points. Then, the aptitude value R is obtainedby summing up both numerical values R1, R2 (S04-5). In this example, theaptitude value R becomes 5 points. Then, the obtained aptitude value Ris stored as the aptitude value of the corresponding divided region B inthe aptitude value memory part 46. The above-mentioned operation isperformed with respect to all the divided regions B (S04-6). Here, FIG.8 shows a specific example in which the aptitude values R obtained withrespect to all the divided regions B are described at the positions ofthe respective divided regions B.

The candidate region determining part 25 determines the projectioncandidate region C out of all the divided regions B based on theaptitude value R stored in the aptitude value memory part 46. In thisdetermination, a reference aptitude value Rc which becomes a criterionfor determining whether or not the divided region B is suitable as aprojection candidate region C is used. The reference aptitude value Rcis stored in the basic information memory part 49 of the memory 20 b.Here, the reference aptitude value Rc in this embodiment is 5 points.

The candidate region determining part 25, first of all, reads thereference aptitude value Rc from the basic information memory part.Next, the candidate region determining part 25 selects one dividedregion B and reads the aptitude value R of the selected divided region Bfrom the aptitude value memory part 46. Then, the candidate regiondetermining part 25 determines whether or not the read aptitude value Ris equal to or more than the reference aptitude value R and, when it isdetermined that the aptitude value Rc is equal to or more than thereference aptitude value Rc, the divided region B subjected to thedetermination is determined as a projection candidate region C and theinformation on the determination is stored in the candidate regionmemory part 47. On the other hand, when the aptitude value R is lessthan the reference aptitude value Rc, information that the dividedregion B subjected to the determination is not the projection candidateregion C is stored in the candidate region memory part 47. Suchprocessing is performed with respect to all the divided regions B, and 0or more projection candidate regions C are determined. For example, inthe case shown in FIG. 8, the candidate region memory part 47 storesinformation that a plurality of divided regions (divided regions having5 points) B in which a point (numerical value of the reference aptitudevalue Rc) is surrounded by a circle are determined as the projectioncandidate regions C.

When the candidate region determining part 25 determines that there isno projection candidate region C (the number of projection candidateregions C being 0) as the result of reference to the reference aptitudevalue Rc, in this embodiment, all the divided regions B are determinedas the projection candidate regions C. When there is no projectioncandidate region C, it may be possible to execute processing whichprojects no image. However, when such processing is executed, a viewercannot observe the image at all. Accordingly, in such a case, one ormore arbitrary or suitable divided regions B may be selected as theprojection regions D. In this embodiment, eventually, the wholeprojection area A is selected as the projection region D. By adoptingsuch processing, the image is displayed on the whole projection area Aand hence, the viewer can observe the image.

The projection region determining part 26 is provided for selecting theprojection region D for actually displaying the image out of theprojection candidate regions C. Here, even when the image to be actuallydisplayed is displayed in a zooming manner, an aspect ratio of theactually displayed area is equal to an aspect ratio of a shape of theprojection area A which is a maximum range in which the image can bedisplayed. Here, although various selecting methods of the projectionregion D are considered, in this embodiment, as will be explained next,when a maximum similar figure which falls within a region constituted ofthe projection candidate region C out of similar figures similar to theshape of the projection area A overlaps with the area constituted of theprojection candidate region C, the projection candidate region C whichoverlaps with the maximum similar figure is selected as theabove-mentioned projection region D. Here, the shape of the projectionarea A is stored in the basic information memory part 49 of the memory20 b as a shape of projection range of the projection light L.

As described in a flowchart shown in FIG. 16, the projection regiondetermining part 26, first of all, reads whether or not the dividedregions which are not the projection candidate region C (herein afterreferred to as non-projection candidate region) UC exist from thecandidate region memory part 47 (S06-1). Here, when all the dividedregions B are the projection candidate regions C (S06-2), all theprojection candidate regions C are selected as the projection regions D(S06-3). On the other hand, when the non-projection candidate regions UCexist, the projection candidate region C which constitutes the center ofa range in which the image is displayed is detected in the followingmanner. This processing is explained in conjunction with FIG. 9A to FIG.9C and FIG. 10A to FIG. 10C.

First of all, with respect to all the non-projection candidate regionsUC, a first excluded region E1 shown in FIG. 10A whose center is placedin each non-projection candidate region UC is obtained. For this end,first of all, initial setting of the first excluded candidate region Ed1is read from the basic information memory part 49 (S06-4). The shape ofthe first excluded candidate region Ed1 is similar to the shape of theprojection area A and the size of the first excluded candidate regionEd1 is, even when the divided region B positioned in an outermostperiphery of the projection area A is the non-projection candidateregion UC, set to a size which allows the first excluded candidateregion Ed1 to cover the center of the projection area A. In thisembodiment, the first excluded candidate region Ed1 is indicated byhatching in FIG. 9A and agrees with a range of the divided regions Bcorresponding to two layers surrounding the divided region B11.

Further, along with the obtainment of the first excluded region Ed1, asecond excluded region Ed2 having a frame shape shown in FIG. 11Bextending toward the inside of the projection area A from an outerperiphery of the projection area A by a predetermined thickness isobtained. For this end, first of all, initial setting of the secondexcluded candidate region Ed2 is read from the basic information memorypart 49 (S06-4). A size of the second excluded candidate region Ed2 ininitial setting is, in this embodiment, set to a size indicated byhatching in FIG. 9B. Although the size of the second excluded candidateregion Ed2 agrees with a range of the divided regions B corresponding totwo layers on a peripheral side of the projection area A, the size ofthe second excluded candidate region Ed2 is a size which allows thesecond excluded candidate region Ed2 to cover the whole range of theprojection area A.

Next, by overlapping both of the excluded candidate regions Ed1, Ed2 tothe projection area A, the projection candidate regions C which areincluded in neither one of regions Ed1, Ed2 are detected (S06-5). Whensuch projection candidate regions C exist, one of the projectioncandidate regions is selected as the center of the projection range(S06-6). In the example explained above, as shown in FIG. 9C, the wholedivided regions B are included in either one of regions Ed1, Ed2 andhence, the projection candidate region C which is included in neitherone of regions Ed1, Ed2 does not exist.

In this case, subsequently, with respect to intersections Px of dividinglines of the divided regions B, the intersection PX which becomes thecenter of a range for displaying the image is detected. To explain morespecifically, out of intersections Px, the intersections Px which arenot included in the excluded candidate regions Ed1, Ed2 are detected(S06-7). When such intersections Px exist, one of the intersections Pxis selected as the center of the projection region D (S06-8). However,in the example explained above, such an intersection Px does not alsoexist.

When neither the projection candidate region C which becomes the centerof the projection range nor the intersection Px which becomes the centerof the projection region D is detected, excluded regions smaller thanthe excluded candidate regions Ed1, Ed2 used in this processing by onestep are prepared and are read as the excluded candidate regions Ed1,Ed2 (S06-9). Then, when the first excluded candidate region Ed1 is notas large as the one divided region B in size (S06-10) or when the sizeof the second excluded candidate region Ed2 is not 0 although the firstexcluded candidate region Ed1 is as large as one divided region B(S06-11), processing as same as the above-mentioned processing isperformed using the newly-read excluded candidate regions Ed1, Ed2 thusdetecting either one of the projection candidate region C and theintersection Px which constitutes the center of the projection region D.Such processing is repeated until the projection candidate region C orthe intersection Px which becomes the center of the projection region Dcan be detected (S06-5, 7, 9 to 11).

In the example explained above, the region indicated by hatching shownin FIG. 10A is prepared as the first excluded candidate region Ed1smaller than the projection area A by one stage. This region fallswithin a range of the divided regions B corresponding to one layersurrounding the divided region B11. Here, although a shrinking rate ofthe first excluded candidate region Ed1 can be appropriately selected,the newly provided first excluded candidate region Ed1 is set similar tothe shape of the projection area A. Further, a region indicated byhatching shown in FIG. 10B is prepared as the second excluded candidateregion Ed2 having a size smaller than the projection range A by onestage. The region falls within a range of the divided region Bcorresponding to one layer on the outer peripheral side of theprojection area A. Although a shrinking rate of the second excludedcandidate region Ed2 region can be suitably selected, the preparedsecond excluded candidate region Ed2 is set such that a shape of thesecond excluded candidate region Ed2 becomes similar to a shape of theprojection area A.

In this manner, when necessary, the excluded candidate regions Ed1, Ed2whose sizes are gradually decreased are provided. When a range of thefirst excluded candidate region Ed1 becomes equal to a range of thedivided regions B which are not the projection candidate regions C, thatis, becomes equal to a range of non-projection candidate region UC(S06-10) and a range of the second excluded candidate region Ed2 becomes0 (S06-11) before the projection candidate region C or the intersectionPx which constitutes the center is detected, any one of the projectioncandidate regions C is selected as the projection region D (S06-12).

As shown in FIG. 10C, when excluded candidate region Ed1, Ed2 which issmaller by one step is overlapped with the projection area A, sincethree divided regions B23, B32, B33 are present as the projectioncandidate regions C which are included in neither excluded candidateregion Ed1 nor Ed2 (S06-5), one out of three divided regions is selectedas the center of the projection range (S06-6). In this example, thedivided region B33 is selected. Here, the intersections Px which areincluded in neither excluded candidate region Ed1 nor Ed2 are, forexample, intersections Px shown in FIG. 10C. In the example explainedhere, the projection candidate region C which constitutes the center ofthe projection range is detected in advance and hence, the processingfor detecting the intersection Px is not executed.

Next, under conditions that the selected divided region B33 ispositioned at the center, has a shape similar to the shape of theprojection area A and is not overlapped with the non-projectioncandidate region UC, a projection region selection region Dd having amaximum size is detected (S06-13). In the example explained here, theprojection region selection region Dd can be determined depending on thenumber of layers that the divided regions B surrounding the dividedregion B11 can increase. Then, the region indicated by hatching in FIG.11 is detected as the projection region selection region Dd.

Here, the projection candidate region C which is overlapped with theprojection region selection region Dd is selected as the projectionregion D (S06-14), and the selected divided region B is stored in theprojection region memory part 48 as the projection region D. In theexample shown in FIG. 11, nine divided regions B22, B23, B24, B32, B33,B34, B42, B43, B44 are stored in the projection region memory part 48 asthe projection region D. In this manner, in the projector 10 of thisembodiment, it is considered that the candidate region determinationpart 25 and the projection region determination part 26 as a wholecorrespond to a region selection unit.

Here, even when the intersection Px is detected as the center of theprojection range instead of the projection candidate region C, theprojection region D is selected in accordance with similar steps. Inthis case, in step corresponding to step “S06-13” in the flowchart shownin FIG. 16, one intersection Px is selected out of the detectedintersections Px, and the number of layers that the divided regions Bsurrounding the selected intersection Px can increase is calculated andthe projection region selection region Dd is detected based on thecalculation. Here, in step corresponding to step “S06-14”, theprojection candidate region C overlapped with the projection regionselection region Dd is selected as the projection region D and theselection is stored in the projection region memory part 48. Here, sincethe basic flowchart of the above-mentioned processing is similar to theflowchart of the processing shown in FIG. 16, the explanation thereof isomitted.

The image processing part 27 is, to allow an image to be displayed in aprojection range formed of the selected projection region D, constitutedof an image size control part 27 a for obtaining anenlargement/shrinkage ratio of an image, and a projecting directioncontrol part 27 b for obtaining the projecting direction X of theprojection light L. Here, the image size control part 27 b, forobtaining the enlargement/shrinkage ratio and the projecting directionX, first of all, reads the divided region B selected as the projectionregion D from the projection region memory part 48.

The image size control part 27 a obtains a size of the projection rangeconstituted of the read projection region D. Here, the image sizecontrol part 27 a obtains the enlargement ratio or the shrinkage ratioof the image to be projected by comparing the size of the obtainedprojection range and the size of the projection area A, and the obtainedenlargement/shrinkage ratio is stored in the basic information memorypart 49. The image size control part 27 a performs image processing suchthat a pure black image is displayed within a range in the projectionarea A where an image is not projected. Due to such a constitution, itis possible to prevent an excess light from entering the image fromperipheries thus making the displayed image more easily visible. In thisembodiment, the enlargement ratio or the shrinkage ratio obtained hereis used for controlling a zooming motor 15 b of the zooming unit 15 ofthe projection lens part 13.

The projecting direction control part 27 b obtains the center positionof the projection range constituted of the read projection region D, andobtains the projecting direction X along which the image is projected onthe obtained center position. The obtained projection direction X isused for controlling the light source control part 12 b of the lightsource unit 12.

The focusing control part 28 is provided for controlling the focusing ofthe projection lens 14. The focusing control part 28 reads an evaluationdistance Le of the divided region B positioned at the center or in thevicinity of the center of the projection region D from the evaluationdistance memory part 44 and, at the same time, reads theenlargement/shrinkage ratio from the basic information memory part 49.Then, the focusing control part 28, based on these data, obtains aposition of the projection lens 14 at which an image displayed on thescreen S becomes sharp, and the obtained position of the projection lens14 is stored in the basic information memory part 49. Here, the obtainedposition is used for controlling the focusing unit 16.

The light quantity control part 29 is provided for controlling a lightquantity of the light source 12 a. The light quantity control part 29,first of all, out of the projection region D, reads the evaluationdistance Le of the divided region B which is closest to the center ofthe projection range where the image is actually displayed from theevaluation distance memory part 44. Then, the light quantity controlpart 29, based on the evaluation distance Le, obtains a light quantitywhich makes the image displayed on the screen S easily visible, and theobtained light quantity is stored in the basic information memory part49. The obtained light quantity is used for controlling a light quantityof the light source 12 a. Here, the light quantity may be alsocontrolled by taking the enlargement/shrinkage ratio of the image storedin the basic information memory part 49 into consideration.

The manner of operation of the respective parts of the projector 10 whenan image is projected on the screen S using such a projector 10 isexplained in conjunction with the flowchart in FIG. 12.

When the power source switch of the projector 10 is turned on, firs tofall, the positions of the centers Bc of the respective divided regionsB in the inside of the projection area A are measured using therespective distance sensors 19 of the sensor unit 18 shown in FIG. 1 orthe like (S01).

Upon measurement of the positions of the centers Bc of the respectivedivided regions B, the evaluation positions Pe and the evaluationdistances Le of the respective divided regions B are obtained by theevaluation position arithmetic operation part 22 of the controller 20shown in FIG. 4 (S02). Here, the positions of the centers Bc (reflectionpoint position) are measured by infrared rays Ir for distance detectionradiated to the centers Bc of the respective divided regions Bc, and theevaluation positions Pe and the evaluation distances Le are obtainedbased on the measured positions. The evaluation positions Pe and theevaluation distances Le are converted into values which are expressed asthe positions and the distances with respect to the projection lens 14.

After the evaluation positions Pe and the evaluation distances Le areobtained, as next step, the obstacle detecting part 23 detects anobstacle W or the unevenness present in each divided region B using theevaluation position Pe in each divided region B. To explain thisdetection processing schematically, it is determined whether or notthree selected evaluation positions Pe are positioned on one straightline and, at the same time, the spaced-apart distances G from a linesegment constituting the reference obtained at the time of determinationto the respective evaluation positions Pe are obtained (S03). Steps forobtaining the spaced-apart distances G are explained in detail using aflowchart shown in FIG. 14 and hence, the detailed explanation of stepsis omitted here.

After the spaced-apart distances G are obtained with respect to allevaluation positions Pe, the aptitude value arithmetic operation part 24obtains aptitude values R of the respective divided regions B as theprojection surfaces using the spaced-apart distance G and the evaluationdistance Le (S04). The spaced-apart distances G are suitable asnumerical values for determining whether or not the obstacle exist inthe corresponding divided region B or whether or not the unevennessexists in the corresponding divided region B. Further, the evaluationdistance Le is suitable as a value for determining whether the positionof the screen S falls within a proper range for the projector 10 or not.Accordingly, using such numerical values, the aptitude value R of thecorresponding divided region B as the projection surface can beadequately obtained. Here, the procedure for obtaining the aptitudevalue R is explained in detail using the flowchart shown in FIG. 15.

After the aptitude values of the respective divided regions B areobtained, as next step, the candidate region determination part 25determines the projection candidate region C among the sixteen dividedregions B using the aptitude values R (S05). To be more specific, thecandidate region determination part 25 compares the aptitude values ofthe respective divided regions B with the reference aptitude value Rcand determines the divided region B whose aptitude value R is thereference aptitude value Rc or more as the projection candidate regionC.

After the projection candidate region C is determined, the projectionregion determination part 26 selects the projection region D to actuallydisplay the image out of the divided regions B determined by theprojection candidate region C (S06). The projection candidate region Cis a portion of the projection area A which substantially possesaptitude as the projecting surface. However, it is not always limitedthat all the projection candidate regions C are included in theprojecting range to display the image. In this regard, the projector 10according to this embodiment automatically select the projection regionD on which the image is actually projected out of the projectioncandidate region C and hence, the image can be displayed speedily andsurely only in the area having no obstacles and no unevenness. Here, theprocedure for selecting the projection region D is explained in detailusing the flowchart shown in FIG. 16.

After the projection region D is selected, the image processing part 27performs image processing so that the image to be displayed is displayedon a projection range constituted of the selected projection region D(S07). To be more specific, the image size control part 27 a modifiesthe image to be displayed by enlargement or shrinkage and, theprojection direction control part 27 b determines the projectiondirection X of the image to be displayed so that the image can bedisplayed within the projection range. Due to such a method, the imagehaving a suitable size can be surely displayed on the projection rangeconstituted of the selected projection region D.

For example, as shown in FIG. 17B, when the image is projected from theprojector 10 placed above the screen S which extends horizontally towardthe screen S, a case in which a notebook computer WP is placed on theleft upper corner of the projection area A is considered. Here, when thenotebook computer WP is detected as an obstacle W in a divided regionB11, the divided region B indicated by hatching in FIG. 11 is selectedas the projection region D and hence, the image is displayed in a stateshown in FIG. 17B. Here, when all divided regions B are selected as theprojection regions D, as shown in FIG. 17A, the image is displayed onthe whole projection area A. Further, when a plurality of obstacles Wsuch as the notebook computers WP is present, as shown in FIG. 17C, theimage is displayed on portions of the projection area A.

Then, the focus control part 28 adjusts focusing of the projection lens14 so that a clear image is displayed on the screen S (S08). Further,the light quantity control part 29 adjusts a quantity of light from thelight source 12 a so that the image with brightness sufficient for easyviewing is displayed on the screen S (S09). By performing such acontrol, a clear image having proper brightness can be surely displayedon the projection range on the screen S.

As has been described above, according to the projector 10 of thisembodiment, out of the projection area of the projector, a rangesuitable for a projection surface having no obstacle W or unevenness canbe detected. Then, the projection light L is projected toward the rangesuitable for the projection surface so as to display the image on thisprojection range. When the image is displayed on a region having theobstacle W or unevenness, the image is displayed in a distorted state ora stepped portion is formed in the middle of the image and hence, theremay be a case in which the image cannot be accurately viewed.

In this respect, according to the projector 10 of this embodiment, theimage can be displayed in the range having no obstacle W or unevennessand suitable for the projection surface and hence, it is possible toprevent distortion or a stepped portion in the image thus enabling thedisplay of the easily viewable image.

Here, in the projector 10 of this embodiment, infrared rays Ir are usedas detection waves. However, the detection waves are not limited to theinfrared rays Ir, and laser beams or ultrasonic waves may be used as thedetection waves.

Further, in the projector 10 of the above-mentioned embodiment, theinfrared rays Ir of the distance sensor 19 for detecting distance areradiated toward a position of the center Bc of each divided region B soas to obtain an evaluation position Pe of the corresponding dividedregion B. However, the evaluation position Pe may not be the positionrelating to the center Bc of the divided region B. For example, anevaluation position acquired with respect to an arbitrary position inthe inside of the corresponding divided region B may be used as theevaluation position Pe. Here, in the above-mentioned embodiment, aposition measuring place is only one place constituted of the center Bcfor each divided region B, and the evaluation position Pe of the dividedregion B is obtained based on the portion. However, a method forobtaining the evaluation position Pe is not limited to such a method.For example, positions of a plurality of places in the divided region Bmay be measured and the evaluation position Pe of the correspondingdivided region B may be obtained based on the measured positions of theplurality of places, or an average position of the plurality of measuredpositions may be used as the evaluation position.

Second Embodiment

Next, a projector of a second embodiment is explained.

In an explanation of a second embodiment, the constitution differentfrom the constitution of the projector 10 of the above-mentionedembodiment is mainly explained, and with respect to the parts commonwith the parts in the constitution of the projector 10 of theabove-mentioned embodiment is given the same symbol and the explanationthereof is omitted.

As shown in FIG. 18, the projector 60 of the second embodiment includesan imaging unit 61 which includes CCD cameras 61 a, 61 b as means formeasuring a distance from a projection area A to a divided region B. Thesecond embodiment differs from the above-mentioned embodiment 1 withrespect to this constitution. Here, the projector 60 of the secondembodiment, as described later, includes a color detector 62 fordetecting color of each divided region B in the projection area A and acolor memory part 81 for storing data relating to the colors detected bythe color detector 62. The second embodiment differs from theabove-mentioned embodiment also with respect to this constitution (seeFIG. 19).

Further, as described later, in this embodiment, color is taken intoconsideration when an aptitude value R is obtained with respect to theprojection surface of each divided region B and hence, the projector 60includes a color arithmetic operation part 71 for detecting the color ofeach divided region B. Here, this embodiment differs from theabove-mentioned embodiment in a method for obtaining the aptitude valueR and hence, a controller 70 includes an aptitude value arithmeticoperation part 72 different from the aptitude value arithmetic operationpart of the above-mentioned embodiment.

As shown in FIG. 18 and FIG. 19, the imaging unit 61 includes a rightCCD camera 61 a, left CCD camera 61 b and an imaging point positionarithmetic operation unit 61 c for calculating a position with respectto a predetermined position in an imaging range or a distance.

The right CCD camera 61 a and the left CCD camera 61 b are arranged onboth sides of the projection lens part 13. That is, the right CCD camera61 a and the left CCD camera 61 b sandwich the projection lens part 13there between. Here, the both CCD cameras 61 a, 61 b are directed in thedirection in which an image of the whole projection area A on theprojection surface can be picked up when the projection surface such asthe screen S is arranged within a proper range of the projectiondistance of the projection 60. The proper range of the projectiondistance is usually preliminarily set for each projector based on anoutput of the light source of the projector or the like. Further, theimages picked up by the both CCD cameras 61 a, 61 b are inputted to theimaging point position arithmetic operation unit 61 c.

The imaging point position arithmetic operation unit 61 c is providedfor detecting the obstacle W or the unevenness in the inside of theprojection area A using a detection method for detecting a distancebased on a parallax image. This detecting method is, to schematicallyexplain, a method for detecting a parallax between the parallax imagesbased on a plurality of parallax images obtained by viewing an object tobe picked up from different viewing points and detecting a depth such asunevenness of the object to be picked up based on the detected parallax,and a generally well-known method in an image processing field and animage recognition method. Accordingly, the detailed explanation of themethod is omitted.

In the imaging unit 61, first of all, matching is performed using twoinputted images as the parallax images so as to detect a parallaxquantity between the parallax images. To explain specifically, forexample, one specific point corresponding to the center Bc of eachdivided region B in the projection area A is obtained on the imagepicked up by the right CCD camera 61 a, while another specific pointcorresponding to the one specific point is obtained on the image pickedup by the left CCD camera 61 b. In this manner, after the both specificpoints corresponding to each other are obtained, a movement distance,that is, a parallax quantity on the parallax image is obtained withrespect to the position of the center Bc of each divided region B.

Then, based on the obtained parallax quantity, by making use of theprinciple of triangulation, the position of the center Bc of eachdivided region B is obtained and, at the same time, a distance betweenthe center Bc of each divided region B (see FIG. 3A) and the right CCDcamera 61 a (and/or the left CCD camera 62 a is obtained. The obtainedposition and distance are stored in a center position memory part 42 ofa memory 70 b described later by way of the controller 70.

The image pick-up unit 61 constitutes a portion of the color detector 62for detecting color of each divided region B.

The color detector 62 is constituted of the light source 12 a, the rightCCD camera 61 a for picking up the projection area A and the colorarithmetic operation part 71 provided to the arithmetic operation part70 in the projector 60.

The light source 12 a is used as a unit for projecting white lighttoward the inside of the projection area A. Here, the right CCD camera61 a picks up each divided region B in a state that the white light isprojected, and the picked-up image is inputted to the color arithmeticoperation part 71. Here, as a CCD camera which constitutes the colordetector 62, the left CCD camera 61 b may be used, or the both CCDcameras 61 a, 61 b may be used.

Further, the color arithmetic operation part 71 obtains color of eachdivided region B based on a signal relating to the image outputted bythe right CCD camera 61 a. Color has three attributes consisting ofluminosity, hue and chrominance, and the color arithmetic operation part71 obtains the luminosity M and the hue N out of these three attributes.Then, the luminosity M and the hue N obtained with respect to eachdivided region B are stored in the color memory part 81 of the memory 70b. Various kinds of cameras can be used as the CCD camera. However, inthis embodiment, a camera which outputs RGB signals is used.Accordingly, the color arithmetic operation part 71 obtains theluminosity M and the hue N based on the outputted RGB signals. As amethod for obtaining the luminosity M and the hue N, various well-knownmethods such as a method using an RGB lookup table, for example, or thelike exist in a field of an image apparatus and hence, the explanationof the method is omitted here. Here, the luminosity M is specified witha numerical value between 100 (pure white) and C (pure black), and adegree of coloration of the hue N is specified with a numerical valuebetween 100 (achromatic color) and 0 (any one of three primary colors).Here, the luminosity M and the hue N obtained with respect to eachdivided region B are stored in the color memory part 81 of the memory 70b.

Here, although this embodiment is configured such that the colorarithmetic operation part 71 is provided to the controller 70, thepresent invention is not limited to such constitution. For example, whenan image pick up unit such as a CCD camera which outputs a color (hue)signal and a brightness signal is used, the color arithmetic operationpart 71 of the controller 70 may, simply, obtain hue based on intensityof the color signal and obtain luminosity based on intensity of thebrightness signal.

The aptitude value arithmetic operation part 72 obtains an aptitudevalue R for each divided region B based on the spaced-apart distance G,luminosity M and hue N obtained with respect to the evaluation positionPe for each divided region B.

As described in a flowchart shown in FIG. 23, when the aptitude value Ris obtained, the spaced-apart distance G of the corresponding dividedregion B is read from the obstacle information memory part 45 (S15-1).Then, spaced-apart distance table T2 (see FIG. 7B) is read from thebasic information memory part 49, and a numerical value R2 for aptitudevalue calculation is obtained based on the read spaced-apart distance Gby reference to a spaced-apart distance table T2 (S15-2). Further, theluminosity M and hue N of each divided region B are read from the colormemory part 81 (S15-3). A color map table T3 shown in FIG. 20 is storedin the basic information memory part 49, and the aptitude valuearithmetic operation part 72 reads the color map table T3. Then,numerical value R3 for aptitude value calculation is obtained based on avalue obtained by multiplying numerical values of the obtainedluminosity M and hue N and by dividing the value by 100 by reference tothe table T3 (S15-4). Then, by summing the both numerical values R2, R3,the aptitude value R of the selected divided region B is obtained(S15-5). For example, when “largely remote” occurs on a white surface,R2 is 2 points and R3 is 5 points and hence, the aptitude value Rbecomes 7 points. Then, the obtained aptitude value R is stored in theaptitude value memory part 46. Such processing is performed with respectto all divided regions B (S15-6). Here, FIG. 21 shows a specific exampleof the aptitude values R obtained with respect to all divided regions B,wherein the aptitude values R are filled in the respective dividedregions B.

Operations of respective parts in the projector 60 when the image isprojected on the screen S in the projector 60 of the second embodimenthaving the different constitution from the constitution of the firstembodiment is explained by reference to a flowchart shown in FIG. 22.Here, the explanation with respect to processing common with theconstitution shown in FIG. 12 is omitted.

When the power switch of the projector 10 is turned on, the projectionarea A is picked up by the both CCD cameras 61 a, 61 b of the imagingunit 61, and the position of the center Bc of each divided region B ismeasured based on the picked-up image (S11). The measured position ofthe center Bc and a distance between the projector 10 and the positionare stored in the center position memory part 42.

Next, the evaluation position arithmetic operation unit 22 of thecontroller 70 shown in FIG. 19 converts the position stored in thecenter position memory part 42 into a position expressed as a positionwith respect to the projection lens 14, and the position obtained byconversion is stored in the evaluation position memory part 43 as anevaluation position Pe of the corresponding divided region B (S12).Here, an evaluation distance Le may be obtained simultaneously and bestored in a suitable memory part.

After the evaluation position Pe is obtained, subsequently, the obstacledetection part 23 obtains a spaced-apart distance G of the evaluationposition Pe of each divided region B from a line segment whichconstitutes reference (S13). The spaced-apart distance G is suitable fora numerical value for determining whether or not an obstacle W ispresent in the corresponding divided region B and whether or notunevenness is present in the corresponding divided region B. Here, stepsfor obtaining the spaced-apart distance G has been explained in detailusing the flowchart shown in FIG. 14 which is used in the explanation ofthe above-mentioned embodiment. Accordingly, the detailed explanation isomitted here.

Further, the color arithmetic operation part 71 obtains the luminosity Mand the hue N for each divided region B (S14). The luminosity M and thehue N are suitable as numerical values for determining whether or not asurface of the screen S is suitable for the projection surface.

After the spaced-apart distance G, luminosity M and hue N of theevaluation position Pe are obtained, first of all, the numerical valueR2 for the aptitude value calculation is obtained by the aptitude valuearithmetic operation part 24 based on the spaced-apart distance G, andthe numerical value R3 for the aptitude value calculation is obtainedbased on the luminosity M and hue N (S15). Then, based on thesenumerical values R2, R3, an aptitude value R of each divided region B asa projection surface is obtained. Here, steps for obtaining the aptitudevalue R have been explained using the flowchart shown in FIG. 23 andhence, the explanation of steps is omitted.

After the aptitude values R for the respective divided regions B areobtained, subsequently, the candidate region determining part 25determines a projection candidate region C from 16 divided regions Busing the aptitude values R (S16). Next, a projection region D on whichthe image is actually displayed is selected out of the divided regions Bdetermined as the projection candidate regions C by the projectionregion determining part 26 (S17). Then, the image processing part 27performs the image processing so that the image can be displayed in aprojection range constituted of the selected projection regions D (S18).Then, to display a clear image on the screen S, the focusing controlpart 28 adjusts the focusing of the projection lens 14 (S19) and, todisplay an image having brightness suitable for easy viewing on thescreen S, the light quantity control part 29 adjusts a quantity of lightfrom the light source 12 a.

Due to such constitution, it is possible to display an easily viewableimage having neither distortion nor stepped portions can be easilydisplayed on a region which has no obstacle W or unevenness and issuitable as the projection surface. The processing (S16 to S20) from thestep in which the projection candidate region C is determined based onthe aptitude value R of the respective divided region B to the step inwhich the light quantity is adjusted is substantially equal to theprocessing used in the projector 10 of the first embodiment and hence,the explanation of the processing is omitted here.

Here, in the projector 60 of the second embodiment, the unit includesthe imaging point position arithmetic operation unit 61 c. However, forexample, the controller 70 may include the imaging point positionarithmetic operation unit 61 c. In the projector 60 of the secondembodiment, a so-called matching processing method is used as a methodfor obtaining parallax quantity. However, the method is not limited tothis method, and various methods such as the Hough transform processingmethod which do not require corresponding point determinationprocessing, for example, may be used.

Further, the following techniques may be applicable to the projectors10, 60 in both of the above-mentioned two embodiments.

For example, in this embodiment, a shape of the projection area A (seeFIG. 2 and FIG. 3) and a shape of the divided region B has a laterallyrectangular shape. However, the shapes are not limited to such shapes,and various shapes including a circular shape may be adopted. However,from a viewpoint of effective use of the projection area A, the dividedregion B favorably has a shape similar to the shape of the projectionarea A, and favorably has a quadrangular shape, particularly,rectangular shape or square shape. The number of the plurality ofdivided regions B is 16. However, the number has no upper limit and canbe suitably determined if necessary.

Further, in this embodiment, the number of the places where the positionis measured is only one place which is the center Bc for each dividedregion B, and the evaluation position Pe for each divided region B isobtained based on the one place. However, the method for obtaining theevaluation position Pe is not limited to such manner. For example, bymeasuring positions of a plurality of places in each divided region B,the evaluation position of the corresponding divided region B may beobtained based on the positions of the plurality of measured places, oran average position of the plurality of measured places may be used asthe evaluation position Pe.

In the first embodiment, the distance sensors 19 the number of which isas same as the number of the divided regions B are provided and eachdistance sensor 19 measures a position (reflection point positions) ofthe center Bc of the corresponding divided region B. However, thedistance sensors are not limited to such constitution. For example, byproviding a distance sensor which can measure distances with respect toa large number of positions by scanning, the distance from the distancesensor to the centers Bc of the respective divided regions B may bemeasured by this distance sensor. Further, in the second embodiment, thenumber of positions for obtaining the parallax quantity may be plural.Here, the evaluation position Pe is expressed as a position which isdetermined with respect to the position of the projection lens 14 as thereference position. However, the reference position is not limited tothe position of the projection lens 14, and various positions such as aposition of the light source 12 a, for example, may be used as thereference position.

Further, in the obstacle detection part 23 of the above-mentionedembodiment, as explained above, when all the line segments FL, FS1, FS2are not parallel to the first reference line V, it is determined thatthe spaced-apart distances G is not measurable with respect to threeevaluation positions Pe1, Pe2, Pe3 (see FIG. 14, S03-4-9). When it isdetermined that the spaced-apart distances G is not measurable, as shownin the spaced-apart distance table T2 in FIG. 7B, the numerical value R1for calculating the aptitude value R is set to a low value of “1” andthis case is similarly treated with the case in which an obstacle W orunevenness exists. For example, in a device which detects the obstacle Wor the unevenness using obstacle detection part 23 after the screen S isarranged in a state that the directions of the whole screen S isorthogonal to the projection direction X, when it is determined that themeasurement is impossible, there is a high possibility that the obstacleW or the unevenness exists in all of three selected divided regions B.Accordingly, the case in which the spaced-apart distances G is notmeasurable and the case in which the obstacle W or the unevenness existscan be treated similarly. However, when the obstacle W or the unevennessis detected without detecting a setting state of the screen S, it isnecessary to take a case in which the whole screen S is inclined withrespect to the projection direction X into consideration. That is, whenthe whole screen S is inclined with respect to the projection directionX, there may be a case in which, even though all the line segments FL,FS1, FS2 are not parallel to the first reference line V, threeevaluation positions Pe1, Pe2, Pe3 are arranged on one straight linewhen focusing on only the evaluation positions Pe1, Pe2, Pe3 arefocused.

Accordingly, when the obstacle W or the unevenness is detected withoutdetecting the setting state of the screen S, as described in a flowchartshown in FIG. 24, before performing processing (S03-4-1) for selectingthree evaluation positions Pe1, Pe2, Pe3 and specifying extendingdirections of three line segments FL, FS1, FS2, the obstacle detectionpart 23 performs, first of all, screen state determination processing(S03-4-A) for determining whether or not the direction of the wholescreen S is orthogonal to the projection direction X. Various methodscan be considered as the screen determination method. For example, amethod which obtains the direction of the whole screen S based on theevaluation positions Pe of divided regions B11, B14, B41, B44 at fourcorners of the projection area A can be named.

When the direction of the whole screen S is orthogonal to the projectiondirection X as a result of such determination, as explained above, it isdetermined whether or not the three evaluation positions Pe arepositioned on one straight line (after S03-4-1). On the other hand, whenthe direction of the whole screen S is not orthogonal to the projectiondirection X, the obstacle detection part 23 corrects the direction ofthe whole screen S so that the direction of the whole screen S isorthogonal to the projection direction X (S03-4-B), and the state of thescreen S is determined again (S03-4-A). The correction method may beperformed automatically or may be performed by a person who installs theprojector as one step of a projector installing operation. By performingsuch a correction when necessary, even in a projector which imposes norestriction on a setting state of the screen S, the above-mentionedobstacle detection part 23 may be used.

Further, in the above-mentioned embodiment, both of the obstacle W andunevenness on the screen S are detected using the same reference.However, the obstacle W and unevenness may be detected based ondifferent references. Although the obstacle W and unevenness are commonwith respect to a point that the obstacle W and unevenness impede properimage display, the obstacle W and unevenness differ from each other ininfluence on the image. Accordingly, when the aptitude value R isobtained, the different references may be used for the obstacle W andunevenness respectively. Various methods are considered as a method fordetecting the obstacle W and unevenness based on different references.For example, in the above-mentioned embodiment, when the spaced-apartdistance G obtained with respect to the evaluation position Pe of eachdivided region B is 20 mm or more, it is determined that an obstacle isdetected, while the spaced-apart distance G is less than 20 mm, it isdetermined that unevenness on the screen S is detected. Further, thedetermination based on different references also brings about anadvantage that in performing weighting, the weighting can be performedmore properly.

In the above-mentioned embodiment, the obtained numerical values R1, R2,R3 for calculating the aptitude value are summed to obtain the aptitudevalue R. However, the aptitude value R may be obtained using thenumerical value to which weighting corresponding to the degree ofsignificance is applied. For example, when weighting is applied to thenumerical value R2 for calculating the aptitude value based on thespaced-apart distance G, a value obtained by multiplying the obtainednumerical value R2 by weighting coefficient is actually used as thenumerical value R2 for calculating the aptitude value. Due to such amethod, the more practical aptitude value can be obtained and hence, theprojection candidate region C can be determined based on the morepractical reference.

The method for obtaining the aptitude value R of each divided region Bas the projection surface is not limited to the method used by theprojectors 10, 60 of the above-mentioned two embodiments. For example,it may be possible to adopt a method which obtains the aptitude value Rbased on the numerical value R1 for calculating the aptitude value R1obtained based on the evaluation distance Le, the numerical value R2 forcalculating the aptitude value R2 obtained based on the spaced-apartdistance G and the numerical value R3 for calculating the aptitude valueobtained based on the luminosity. In this case, Tables T1, T2, T3 forobtaining the three numerical values R1, R2, R3 and a reference aptitudevalue Rc corresponding to the method are provided.

In the above-mentioned embodiment, when the projection region D isselected from the projection candidate regions C, the projection regionD is selected such that the projection range in which the image isactually displayed is explained as large as possible. However, otherselection reference may be used. For example, it is possible to adopt aselection reference which allows the selection of the projection regionD in a state that the projection range preferably includes the center ofthe projection area A and, even when the projection range does notincludes the center of the projection area A, the projection range ispreferably arranged close to the center. When a large projection rangeis ensured, a larger image can be displayed and hence, more easilyviewable image can be displayed. On the other hand, using the selectionreference which allows the selection of the projection region D suchthat the position of the projection range is preferably arranged closerto the center of the projection area A, the projection light L includingimages can be projected using a center portion of the optical system ofthe projection lens part 12. In the optical system, in general, thecloser a portion of an optical system to the center portion, the betterthe optical performance becomes. When the projection light L includingthe image can be projected using the center portion of the opticalsystem, the more easily viewable image can be displayed. Either one ofselection references may be adopted, or both selection references may beadopted. When both selection references are adopted, priority isassigned to either of selection references may precede.

As a method for selecting the projection region D so that the projectionrange is preferably positioned as close as possible to the center of theprojection area A, for example, the following method can be named. Whenall divided regions B are determined as the projection candidate regionsC, it is sufficient to display the image in the whole projection area Aand hence, this method is used when the divided region B which is notdetermined as the projection candidate region C exists. First of all,the projection candidate region C which is positioned closest to thecenter of the projection area A is detected out of the projectioncandidate regions C. Then, the projection region selection region Ddhaving the largest size is detected under the condition that theprojection region selection region Dd includes the projection candidateregion C, has a shape similar to the shape of the projection area A and,further, does not overlap with then on-projection candidate region UC.Then, the projection candidate region C which overlaps with theprojection region selection region Dd may be selected as the projectionregion D.

The method for controlling the projection direction of the projectionlight L so that the image is projected on the projection rangedetermined by the projection region D is not limited to theabove-mentioned method which controls the projection direction of theprojection light L using the projection direction control part 27 b, andvarious methods may be used. For example, the projection direction ofthe projection light L may be controlled such that an optical system ofthe projection lens part 13 of the projector 10 which includes the lightsource 12 a and projection lens part 13 is mounted on the projector body10 in a state that the projection direction X is changeable and, at thesame time, by mounting a drive unit such as an actuator which moves theprojection lens part 13 is provided and is operated by the drive unitsuch as the actuator if necessary whereby the projection direction ischanged.

The projectors 10, 60 of the above-mentioned embodiments are formed of aportable-type projector and display the image on a projection surfacesuch as a screen S which extends vertically. However, the projectors maybe formed of a projector of a type other than the portable type such asan installation-type projector.

For example, as shown in FIG. 25, the present invention is alsoapplicable to a projector 90 of a type which displays the image on ascreen S which extends horizontally on a table Ta. Further, in this typeof projector 90, as shown in FIG. 25, if necessary, a sensor 91 forradiating detection waves such as infrared rays Ir in the directionparallel to the extending direction of the screen S is provided todetect the obstacle W on the screen S.

As shown in FIG. 26A, in the projector 90 of the type which is mountedon the table Ta, the projector body 11 which includes the light source12 a and the projection lens 14 for projecting light toward the screen Son the table Ta may be mounted in a state that the projector body 11 isrotated about a vertical axis Va as a rotation axis with respect to thepedestal 92 or may be mounted in a state that the projector body 11 isrotated about a horizontal axis Ha as a rotation axis. By mounting theprojector body 11 in this manner, after the projector 90 is installed onthe table Ta, by rotating the projector body 11 about the vertical axisVa or the horizontal axis Ha, the better projection surface can beeasily selected.

As shown in FIG. 26B, the projector body 11 may be mounted in avertically movable manner with respect to the pedestal 92. By mountingthe projector body 11 in this manner, by vertically moving the projectorbody 11 after the projector 90 is installed on the table Ta, a size ofthe range of the image to be projected on the screen S can be easilyadjusted.

FIG. 27 shows a projector 96 of a type suspended downwardly from aceiling by a support member 95, and this type may be used as theprojector in the present invention. The projector 96 shown in FIG. 27includes three sensors as shown in FIG. 27 as means for detecting theobstacle W or unevenness (a lower-end distance sensor, a middle-stagedistance sensor, an upper-end distance sensor). Here, as shown in FIG.27, the projector may be a projector which projects an image on a screenS of a type which allows viewing of the image on the screen S from theside from which the projection light L is projected, or may be aprojector which projects an image on a screen S of a type which allowsviewing of the image on the screen S from the side opposite to the sidefrom which the projection light L is projected.

Third Embodiment

FIG. 28 is a perspective view of appearance of an image display deviceof a third embodiment.

As shown in FIG. 28, an image display device 110 is a projection devicewhich includes a projection part 114 which generates a projection light112 based on a video signal and projects an image 113 on a table, asupport column 116 which supports a projection part 114 and a pedestal118 which mounts the projection part 114 and a support column 116thereon in an erected manner. The image display device 110 receivesinputting of video signals such as RGB signals from a computer device800, and projects the projection light 112 generated based on theinputted video signals in the direction toward the table.

A projection part 114 radiates the projection light 112 such that atleast a portion of the projection light 112 reaches the pedestal 118. Byforming a projection region 119 where a portion of an image 113 can beformed due to the projection light 112 on the pedestal 118, it ispossible to radiate the projection light 112 at an angle close to aright angle with respect to the table. Accordingly, it is possible todisplay the easily-viewable image 113 with small distortion.

The projection region 119 is a region which receives a portion of theprojection light 112 for displaying a portion of an image using ascattered light of the projection light 112, and also is a region whichconstitutes a portion of a screen.

Since the projection region 119 is a region which displays a portion ofthe image 113, it is desirable to form the projection region 119 into ashape having no stepped portion for preventing the generation of ashadow attributed to the projection light 112 (see FIG. 29 and FIG. 30described later). Further, it is desirable to form the projection region119 into a smooth shape for reducing a distortion of an image to bedisplayed.

Further, with the provision of the projection region 119 to the pedestal118, a mounting surface of the pedestal 118 can be set such that thelarge mounting surface is ensured on an image side. Due to such aconstitution, compared to the conventional image display device, theprojection part 114 and the support column 116 can be mounted in anerected manner close to the center of gravity of the pedestal.Accordingly, the stability of the image display device 110 can beincreased when the image display device 110 is mounted on a table andhence, falling of the image display device 110 can be prevented.

Further, in an example shown in FIG. 28, the pedestal 118 is providedwith a photo detector 126 which functions as an operation switch 124when a user performs an operation associated with the image 113. Thephoto detector 126 is a device which outputs received light informationcorresponding to quantity of received light.

When the user interrupts the projection light 112 which the photodetector 126 receives by extending his/her finger to a position abovethe photo detector 126, the received light information which isoutputted from the photo detector 126 is changed and hence, the imagedisplay device 110 can detect that the photo detector 126 (operationswitch) is operated by the user.

Further, the image display device 110 projects operation functioninformation 122 for informing functions allocated to the operationswitch 124 to the user on a portion of the projected image 113 thusenhancing easy-to-use property enjoyed by the user. Further, to show thepresence of the operation switch 124, a switch identification displayfor identifying a range or a periphery of the operation switch 124 maybe performed on a portion of the projected image 113. The switchidentification display may preferably be performed with a highcomplementary color or high contrast with respect to a background.Further, when the photo detector 126 is used as the operation switch124, the switch identification display may preferably be performed byprojecting a light having a wavelength which is not included in a lighthaving high brightness such as a white light, or an illumination such asa fluorescent lamp.

The embodiment shown in FIG. 28 is directed to a mode in which theoperation switch 124 is provided within the projected image 113.However, a position of the operation switch 124 is not limited to theabove-mentioned position, and the operation switch 124 may be providedoutside the image 113. Further, instead of using the photo detector 126as the operation switch 124, an input unit such as a push button switchcan be used as the operation switch 124.

FIG. 29 and FIG. 30 are side views showing the relationship between aprojection angle θs of the projection light 112 projected from theprojection part 114 and an inclination angle θd in the projection region119. As shown in FIG. 29, when a stepped portion or the like having theinclination angle θd made of an acute angle is present in the projectionregion 119 of the pedestal 118, and the relationship of θs<θd isestablished between the inclination angle θd and the projection angleθs, a shadow due to the projection light 112 is generated and hence, theimage 113 is hardly observed. Accordingly, by making the projectionangle θs larger than the inclination angle θd (θs>θd), the projectionpart 114, the inclination angle θd and the position of the projectionpart 114 are determined. Further, to reduce a distortion of an image tobe displayed, it is desirable to make the inclination angle θd in theprojection region 119 as small as possible and, at the same time, toform the projection region 119 into a smooth shape.

Further, as shown in FIG. 30, by making the projection angle θs largerthan the inclination angle θd (θs>θd) also in a region in which theprojection angle θs is formed of a right angle or an obtuse angle, it ispossible to prevent the generation of a shadow due to the projectionlight 112. Further, to reduce a distortion of an image to be displayed,it is desirable to make the inclination angle θd in the projectionregion 119 as small as possible and, at the same time, to form theprojection region 119 into a smooth shape.

FIG. 31 is a block diagram of a signal processing system of the imagedisplay device 110. As shown in FIG. 31, a projection part 165 of theimage display device 110 includes a light emission unit 159 whichconstitutes a light emitting source for emitting a projection light, astop 160 for adjusting a quantity of light emitted from the lightemission unit 159, an illumination optical system 161 for adjusting anillumination light emitted from the light emission unit 159 to aparallel light, a light modulation unit 162 such as liquid crystal forforming a projection image with respect to the illumination lightemitted from the light emission unit 159, and a projection opticalsystem 163 for forming the projection light 112 by expanding theprojection image.

Further, the projection part 165 of the image display device 110includes a projection driver 164 which, by inputting video signals suchas RGB signals in the projection driver 164 from a computer device 800,performs outputting of a drive signal to the light modulation unit 162,the adjustment of the stop 160, and the adjustment of a light emissionquantity of the light emission unit 159 and, at the same time, adjustsbrightness or coloration of the image which is projected from the imagedisplay device 110, and synthesizes operation function information, amenu image, or another projection information thus outputting theseinformation to the light modulation unit 162. In this manner, theprojection driver 164 functions as a function information generationunit which generates video signals including operation functioninformation for projecting functions allocated to the operation switch124 and outputs the generated video signals to the projection part 114.

Further, the image display device 110 includes an input unit 170 foroutputting operation information when the user performs operationsassociated with an image such as brightness or coloration of the image113, or when the user performs various operations associated with theimage display device 110, an input interface 171 for transmitting theoperation information outputted from the input unit 170 to aninformation processing unit 180 by way of a bus 199, a photo detector126 which outputs received light information such as a voltage signalcorresponding to a quantity of received light and is allowed to functionas the operation switch 124, and a received light information processingunit 178 which obtains the received light information outputted from thephoto detector 126 and transmits the outputted received lightinformation to the information processing unit 180.

Further, image display device 110 includes the information processingunit 180 which performs projection of a help image with respect tohandling of the image display device 110, setting of a projectionlanguage, setting of a projection time, setting of a menu image, settingof selection switch, electricity supply/interruption processing, othercontrols relating to the image display device 110, or a processing ofthe image 113 which is projected from the image display device 110 onthe adjustment of projection position, size, brightness, contrast,gamma, color temperature, tone, sharpness, horizontal position orvertical position of the image 113. An aptitude detection part fordetecting an aptitude as a projection surface is constituted of a photodetector 126, a received light information processing unit 178 and theinformation processing unit 180. The aptitude detection part possesses afunction of a distance information generation unit which generates videosignals including distance information on the image 113 formed by theprojection light corresponding to a distance from a pedestal-118-sideprojection end, and outputs the generated video signals to theprojection part 114. Further, the information processing unit 180 alsofunctions as a projection control part for changing a size of the image113, or a projection position of the image 113 based on the receivedlight information outputted from the photo detector 126.

Further, the image display device 110 includes a RAM 181 which is usedas an operation field when the information processing unit 180 executesprocessing, a ROM 183 for storing various information such as aprocessing program executed by the information processing unit 180 orconstants, and a timer 190 for counting time.

In the inside of the image display device 110, the informationprocessing unit 180, a received light information processing unit 178, aprojection driver 164, respective peripheral circuits including an inputinterface 171, the RAM 181, the ROM 183, the timer 190 and the like areconnected to each other by way of the bus 199, and based on theprocessing program executed by the information processing unit 180, theinformation processing unit 180 can control the respective peripheralcircuits. Here, the processing program executed by the informationprocessing unit 180 can be provided using a recording medium or acommunication. Further, respective peripheral circuits can beconstituted of an ASIC or the like.

Next, the manner of operation of the image display device 110 isexplained. When the video signal such as the RGB signals are inputtedfrom the computer device 800, the projection driver 164 outputs a drivesignal for forming an image to the light modulation unit 162, andinstructs the light emission unit 159 to emit a quantity of light. Dueto such an operation, the projection light 112 for the image is formedand hence, it is possible to project the image 113 to a screen.

In adjusting the projection position, the size, the brightness, thecontrast or the like of the image 113 projected by the image displaydevice 110, a user instructs the projection of a menu image by operatingthe operation switch 124. The received light information processing unit178 or the input interface 171 acquires the operation information on theoperation switch 124 operated by the user, and transmits the obtainedoperation information to the information processing unit 180.

Then, the information processing unit 180 generates projectioninformation for performing the projection of the menu image, and outputsthe generated projection information to the projection driver 164. Theprojection driver 164 which acquires the projection informationsynthesizes information of the menu image with the video signal acquiredfrom the computer device 800, and outputs the synthesized information tothe light modulation unit 162. The user can operate the operation switch124 while looking at the projected menu to adjust the projectionposition, the size, the brightness, the contrast or the like of theimage projected by the image display device 110.

Next, the explanation is made with respect to processing for projectingoperation function information 122 to the image 113. FIG. 32 is aflowchart of processing for projecting operation function information122 to the image 113.

In the image display device 110, when the user is allowed to operate themenu switch, the help switch, or other switch, the processing which isexecuted by the information processing unit 180 advances to step S102“add operation function information in the vicinity of operation switch”(herein after, abbreviated as S102).

In step S102, the information processing unit 180 generates operationfunction information for projecting functions currently allocated torespective operation switches 124 to the image 113, and outputs thegenerated information to the projection driver 164. The projectiondriver 164 executes a processing for synthesizing the operation functioninformation acquired from the information processing unit 180 with thevideo signals such as the RGB signals acquired from the computer device800, and outputs a drive signal to the light modulation unit 162. Thenthe processing advances to next step S104 “radiate projection light”.

In S104, the information processing unit 180 instructs the projectiondriver 164 to allow the light emission unit 159 to emit light thusperforming the radiation of the projection light 112. Then, theprocessing advances to next determination step S106 “operation switchoperated?”.

In S106, the information processing unit 180 executes processing ofwaiting for the user to operate the operation switch 124. When theoperation switch 124 is operated by the user, the information processingunit 180 obtains the information via the light information processingunit 178 or the input interface 171. Then, the processing advances tonext step S108 “execute input operation”.

In S108, the information processing unit 180 executes processingcorresponding to the content of the operation by the user. For example,when the user operates the operation switch 124 to instruct the menuprojection, the information processing unit 180 generates projectioninformation on the menu and output the projection information to theprojection driver 164. After the outputting of the projectioninformation is finished, the processing advances to next determinationstep S110 “additional display existing?”.

In S110, the information processing unit 180 determines whether or notan additional display exists based on the input operation by the user.When the information processing unit 180 determines that the additionaldisplay exists, the processing is branched to S102 and the processingfor projecting the additional operation function information in thevicinity of the operation switch 124 is performed. When the additionaldisplay does not exist, the processing for projecting the operationfunction information 122 is finished and the processing returns to theoriginal routine.

Next, processing for adjusting the image size and the projectionposition of the image 113 is explained. FIG. 33 is a flowchart ofprocessing in which aptitude as the projection surface is detected basedon the received light information received by the photo detector 126 andthe adjustment of the image size and the adjustment of the projectionposition are executed.

When the adjustment of the image size and the projection position isinstructed by a user, for example, when electricity is supplied to theimage display device 110 or after a height of the projection part 114 ischanged relative to the pedestal 118, the processing executed by theinformation processing unit 180 advances to processing in step S202“project calibration-use image having maximum size”.

In S202, the information processing unit 180 generates the video signalincluding distance information which differs in a projecting mannerdepending on the distance from the projection end XB on a pedestal sideand output the video signal to the projection driver 164. The projectiondriver 164, in place of the video signals such as the RGB signalsobtained from the computer device 800, outputs the drive signal forprojecting the calibration-use image 130 including the distanceinformation obtained from the information processing unit 180 to thelight modulation unit 162.

Then, the information processing unit 180 instructs the projectiondriver 164 to allow the light emission unit 159 to emit light and to setthe stop 160. Then, the projection part 165 performs the radiation ofthe projection light to project the calibration-use image 130.

Here, the appearance of the image display device 110 when the imagedisplay device 110 adjusts the image size using the calibration-useimage 130 including the distance information is explained in conjunctionwith FIG. 34. FIG. 34 is a side view of the image display device 110 forexplaining a state that the photo detector 126 receives thecalibration-use image 130 including the distance information and theadjustment of the image size is performed based on the received lightinformation obtained as a result of reception of the calibration-useimage 130.

In the example shown in FIG. 34A, the image display device 110, inperforming the change of the size of the image to be projected, first ofall, projects the calibration-use image 130 having the maximum size. Thecalibration-use image 130 is, as shown in FIG. 34B, for example, animage having characteristic which makes the turn ON/OFF cycle of theimage different depending on a distance from the projection end XB. Asother example of the distance information in the calibration-use image,the image which changes the density of a stripe pattern or latticepattern depending on the distance from the projection end XB may beprojected. Further, the distance information of the calibration-useimage may have a characteristic that the calibration-use image isarranged parallel to the projection end XB on the pedestal 118 side.Further, the distance information may be an image which is projectedonly in the vicinity of the photo detector 126 or may be an image whichis projected only within a range of predetermined distance from theprojection end XB on the pedestal 118 side.

In S202 shown in FIG. 33, when the calibration-use image 130 isprojected, the processing executed by the information processing unit180 advances to next step S204 “calculate turn ON/OFF period of theimage from received light information outputted by photo detector”. Thephoto detector 126 which receives a portion of the calibration-use image130 converts the received light into received light information andoutputs the received light information to the information processingunit 180 via the bus 199.

In S204, the information processing unit 180 performs processing forcalculating the ON/OFF periods based on the received light informationoutputted by the photo detector 126. In calculating the Turn ON/OFFcycle, the Turn ON/OFF cycle can be calculated by counting the number oftime that the brightness is changed while the timer 190 counts apredetermined time, for example. Then, the processing advances to nextstep S206 “calculate distance to pedestal and projection end XB”.

In S206, the information processing unit 180 calculates the distancebetween the photo detector 126 and the projection end XB on the pedestalside based on the Turn ON/OFF cycle calculated based on the distanceinformation which changes a projection manner depending on the distancefrom the projection end XB on the pedestal side and the received lightinformation. In calculating this distance, the information processingunit 180 may obtain and use the information associated with the heightof the projection part 114 relative to the pedestal 118. Then, theprocessing advances to next determination step S208 “image existing atpredetermined position?”.

In S208, the information processing unit 180 determines whether or notthe distance between the photo detector 126 and the projection end XB onthe pedestal side falls within a predetermined distance range anddetermines whether or not the image exists at the predeterminedposition. When the information processing unit 180 determines that thedistance between the photo detector 126 and the projection end XB doesnot fall within the predetermined distance range, the processingadvances to next S210 “project image after shrinking image size”.

In S210, the information processing unit 180 instructs the projectiondriver 164 to output the drive signal for projecting the calibration-useimage 132 having a shrunken size based on the distance between the photodetector 126 and the projection end XB on the pedestal side and, at thesame time, instructs the projection driver 164 to radiate the projectionlight whereby the projection part 165 projects the calibration-use image132 shown in FIG. 34A.

Here, the appearance of the image display device 110 when the imagedisplay device 110 shifts the projection position using thecalibration-use image 130 including the distance information isexplained in conjunction with FIG. 35. FIG. 35 is a side view of theimage display device 110 for explaining a state that the projectionposition is shifted based on the received light information outputted bythe photo detector 126 which receives the calibration-use image.

As shown in FIG. 35, the image display device 110, in changing theprojection position to which the image is projected, first of all,projects and displays the calibration-use image 134. As thecalibration-use image 134, for example, an image having thecharacteristic shown in FIG. 34B is used.

In S210 shown in FIG. 33, after the calibration-use image 134 isprojected, the processing executed by the information processing unit180 advances to next step S212 “calculate shift quantity which enablesprojection of whole image”. The photo detector 126 which receives aportion of the calibration-use image 130 converts the received lightinto received light information and outputs the received lightinformation to the information processing unit 180 via the bus 199. InS212, the information processing unit 180, after performing processingfor calculating the Turn ON/OFF cycle based on the received lightinformation outputted by the photo detector 126, calculates the shiftquantity which enables the projection of whole image.

In next step S214, the information processing unit 180 instructs theprojection driver 164 to output the drive signal for projecting thecalibration-use image 136 (see FIG. 35) whose projection position isshifted to the light modulation unit 162 and, at the same time,instructs the projection driver 164 to radiate the projection lightwhereby the projection part 165 projects the shifted calibration-useimage 136. Then, the processing returns to S208.

In S208, when the information processing unit 180 determines that thedistance between the photo detector 126 and the projection end XB fallswithin the predetermined range, the processing advances to S216 “projectimage with size and position after calibration”.

In S216, the information processing unit 180 outputs the information forprojecting the video signals such as the RGB signals obtained from thecomputer device 800 with the predetermined size and position in place ofthe calibration-use image 130 to the projection driver 164. Theprojection driver 164 outputs the drive signal for projecting the videosignals with the predetermined size and position to the light modulationunit 162. The information processing unit 180 instructs the projectiondriver 164 to allow the light emission unit 159 to emit light and to setthe stop 160. Then, the projection light is radiated to project theimage 113 whose projection size and projection position are adjusted.When the calibration of the projection size and projection position ofthe image 113 are finished, the processing executed by the informationprocessing unit 180 returns to the original routine.

In this manner, the image display device 110 detects the aptitude of theprojection surface by projecting the calibration-use image 130 whichexpresses the distance from the projection end XB on the pedestal sidedepending on the difference in Turn ON/OFF cycle and hence, it ispossible to finish the calibration processing of the size or theprojection position of the image in a short period. Further, by using aCCD or the like having the large number of pixels as the photo detector126, the difference in an image pattern or a pattern of thecalibration-use image 130 can be discriminated within a short period.Here, the change of the image size or the shifting of the projectionposition may be performed by adjusting the optical system orelectrically.

The arrangement of the optical parts in the inside of the projectionpart 114 for realizing the change of the image size or the shifting ofthe projection position is explained in conjunction with FIG. 36.

As shown in FIG. 36, the optical system 148 of the projection part 114includes the light emission unit 159 for emitting projection light, thestop 160 for adjusting the light quantity of light emitted by the lightemission unit 159, the illumination optical system 161 for adjusting theillumination light emitted by the light emission unit 159 to parallellight, the light modulation unit 162 which divides the illuminationlight emitted by the light emission unit 159, forms images forrespective primary colors and synthesize the images, the projection lens144 for projecting light modulated by the light modulation unit 162 tothe screen 149 which constitutes the projection surface and a relay lens143 arranged between the projection lens 144 and the light modulationunit 162 and is movable in the vertical direction.

The light modulation unit 162 includes dichroic mirrors 141 a, 141 b forsplitting the illumination light to respective color components of threeprimary colors of R (RED), G (GREEN), B (BLUE), for example. Further,the light modulation unit 162 includes the light modulation units 162 a,162 b, 162 c which form images for respective split color components.The mirrors 141 c, 141 d have a function of changing the direction oflight, and the mirror 141 e, 141 f have a function of synthesizing therespective primary color components.

The dichroic mirror 141 a splits the white illumination light emitted bythe light emission unit 159 into a B (BLUE) component on a shortwavelength side and other components. In the embodiment explained inconjunction with FIG. 36, the dichroic mirror 141 a reflects the B(BLUE) component and allows the B (BLUE) component to be incident on thelight modulation unit 162 a which forms an image having B (BLUE) colorby way of the mirror 141 d.

On the other hand, the light which passes through the dichroic mirror141 a is incident on the dichroic mirror 141 b. The dichroic mirror 141b reflects the light having R (RED) component and allows the lighthaving the R (RED) component to be incident on the light modulation unit162 b and allows the light having the G (GREEN) component to passthrough the dichroic mirror 141 b and allows the light having the G(GREEN) component to be incident on the light modulation unit 162 c toform the images having R (RED) and G (GREEN) colors. The image havingthe B (BLUE) component and the light having the R (RED) component aresynthesized by the mirror 141 e and, further, the image having the G(GREEN) component is synthesized to the image by the mirror 141 f toform a color image.

The relay lens 143 is telecentric with respect to both of a lightmodulation unit 162 side and a projection lens 144 side, and theprojection lens 144 is telecentric with respect to a relay lens 143side. In this manner, by configuring the relay lens 143 to betelecentric with respect to both of the light modulation unit 162 sideand the projection lens 144 side even though the relay lens 143 isshifted to a position of a relay lens 143′ in the directionperpendicular to the optical axis E, it is possible to prevent adrawback that the optical flux from the light modulation unit 162 sideis displaced from the projection lens 144.

Further, the optical system 148 includes the shift mechanism 146 fordisplacing the relay lens 143 to the optical axis E′ from the opticalaxis E, the zooming and focusing mechanism 142 for adjusting a focallength or focusing of the projection lens 144, and the control unit 145for outputting an instruction to adjust the focal length or focusing tothe zooming and focusing mechanism 142 and, at the same time, outputtingan instruction to control a shift quantity of the optical axis E′ to theshift mechanism 146.

The shift mechanism 146 is a controllable mechanism constituted of adrive mechanism such as a motor, and the shift quantity of the opticalaxis E′ can be controlled based on the shift instruction outputted bythe information processing unit 180 to the control unit 145.

The zooming and focusing mechanism 142 is a controllable mechanismconstituted of a drive mechanism such as a motor, and the focal lengthor focusing position can be controlled based on the zooming instructionor the focusing instruction outputted by the information processing unit180 shown in FIG. 31 to the control unit 145. The zooming and focusingmechanism 142 is constituted of, for example, a group of focusing lensesfor performing an extending operation for focusing the image to beformed on the screen 149, a group of variation lenses moving along theoptical axis E for performing an operation of changing the image sizeand a compensator lenses for correcting inaccurate focusing attributedto the zooming operation.

Due to the constitution of the optical system 138 shown in FIG. 36, byshifting the relay lens 143 parallel to the optical axis E, the image tobe projected on the screen 149 can be translated. In an example shown inFIG. 36, by shifting the optical axis of the relay lens 143 to anoptical axis E′, the projection light 112 is displaced to a projectionlight 112′ whereby the position of the image can be shifted. Further, bygiving the zooming instruction to the control unit 145, the image sizecan be changed. Further, by giving the focusing instruction to thecontrol unit 145, the focusing of the image can be adjusted.

Here, the example of realizing the change of the size of the image andthe shifting of the projection position has been explained inconjunction with FIG. 36. However, the light modulation unit 162 may beconstituted of a single-plate color liquid crystal display element, ormay be constituted of a DMD (Digital Mirror Device) or a reflection-typeliquid crystal element. However, in such a case, the constitution of theillumination optical system 161, the stop 160 and the light emissionunit 159 are modified to correspond to the constitution of the lightmodulation unit 162. Further, to project the image as described in theembodiments explained in conjunction with FIG. 28 and the like, it issufficient to arrange the light emission unit 159 to the illuminationoptical system 161 in the direction orthogonal to the optical axis Ewith respect to the dichroic mirror 141 a. Further, to perform thechange of the size of the image and the shifting of the projectionposition, it is not always necessary to provide the relay lens 143 shownin FIG. 36, and these operations can be performed by moving theprojection lens 144 in the direction orthogonal to the optical axis E orby tilting the projection lens 144.

Further, the distance from the projection end XB on the pedestal sidemay be expressed by difference in projection mode such as difference incoloration or difference in brightness besides difference in Turn ON/OFFcycle as the calibration-use image. When the support column 116 of theimage display device 110 includes a varying mechanism which can vary theheight of the projection part 114 relative to the pedestal 118, the sizeof the image and the projection position can be changed along with thechange of the height of the projection portion and hence, the adjustmentof the image size and the projection position is performed every timethe height of the projection part 114 is changed. Further, by supportingthe projection part 114 on the support column 116 in a rotatable manner(not shown in the drawing), the projection position can be changed moreeasily.

Next, another embodiment of processing for adjusting the image size andthe projection position of the image 113 is explained. FIG. 37 is aflowchart of processing for executing the adjustment of the image sizeand the adjustment of the projection position based on whether or notthe photo detector 126 receives the projection light.

When the adjustment of the image size and the projection position areinstructed by a user, for example, when electricity is supplied to theimage display device 110 is or after the height of the projection part114 is changed relative to the pedestal 118, the processing executed bythe information processing unit 180 advances to processing in step S302“project calibration-use image having maximum size”.

In S302, the information processing unit 180 generates the video signalof single color and outputs the video signal to the projection driver164. The projection driver 164, in place of the video signals such asthe RGB signals obtained from the computer device 800, outputs the drivesignal for projecting the calibration-use image obtained from theinformation processing unit 180 to the light modulation unit 162.

Then, the information processing unit 180 instructs the projectiondriver 164 to allow the light emission unit 159 to emit light and to setthe stop 160. Then, the projection part 165 performs the radiation ofthe projection light to display the calibration-use image. Then, theprocessing advances to next step S304 “shrink calibration-use image by 1step”.

In S304, the information processing unit 180 generates the video signalwhich is obtained by shrinking the size of the above-mentionedcalibration-use image by 1 step and outputs the video signal to theprojection driver 164. The projection part 165 performs the radiation ofthe projection light to display the calibration-use image which isshrunken by 1 step. Then, the processing executed by the informationprocessing unit 180 advances to next determination step S306 “image notexisting?”.

In S306, the information processing unit 180 determines whether or notthe photo detector 126 detects a portion of the calibration-use imageprojected in S304 and, thereafter, determines whether or not the imageexists at a predetermined position. When the information processing unit180 determines that the photo detector 126 detects a portion of thecalibration-use image, the processing returns to S304. Further, when theinformation processing unit 180 determines that the photo detector 126does not detect the calibration-use image, the processing advances toS308 “enlarge image size by predetermined step”.

In step S308, the information processing unit 180 generates the videosignals by enlarging the image size by the predetermined step so as toform a portion of the image 913 in the projection region 119 and outputsthe video signals to the projection driver 164. The projection part 165displays the calibration-use image which is enlarged by thepredetermined step. Then, the processing executed by the informationprocessing unit 180 advances to next step S310 “shift calibration-useimage by 1 step”.

In step S310, the information processing unit 180 generates the videosignal which is obtained by shifting the projection position of theabove-mentioned calibration-use image by 1 step and outputs the videosignals to the projection driver 164. The projection part 165 performsthe radiation of the projection light to display the calibration-useimage which is shifted by 1 step. Then, the processing executed by theinformation processing unit 180 advances to next determination step S312“video image not existing?”.

In step S312, the information processing unit 180 determines whether ornot the photodetector 126 detects a portion of the calibration-use imageprojected in S310 and thereafter, determines whether or not the imageexists at a predetermined position. When the information processing unit180 determines that the photo detector 126 detects a portion of thecalibration-use image, the processing returns to step S310 and, when theinformation processing unit 180 determines that the photo detector 126does not detect the calibration-use image, the processing advances toS314 “shift position of image by predetermined step”.

In step S314, the information processing unit 180 generates the videosignals by shifting the position of the image by the predetermined stepso as to form a portion of the image 913 in the projection region 119and outputs the video signals to the projection driver 164. Theprojection part 165 displays the calibration-use image which is enlargedby the predetermined step. Then, the processing executed by theinformation processing unit 180 advances to next step S316 “projectimage having size after calibration”.

In step S316, the information processing unit 180 instructs theprojection driver 164 to project the video signal such as the RGBsignals obtained from the computer device 800 having the predeterminedsize and at the predetermined position in place of the calibration-useimage 130. The projection driver 164 outputs the drive signal forprojecting the video signals having the predetermined size and thepredetermined position to the modulation unit 162. The informationprocessing unit 180 instructs the projection driver 164 to allow thelight emission unit 159 to emit light and to set the stop 160. Then, theprojection light is radiated to project the image 113 whose projectionsize and projection position are adjusted. When the calibration of theprojection size and the projection position are finished, the processingexecuted by the information processing unit 180 returns to the originalroutine.

In this manner, the image display device 110 can automatically changethe size or projection position of the image based on whether or not thephotodetector receives the projection light. Accordingly, the imagedisplay device 110 can project the image having suitable size orsuitable position by changing the size or the projection position of theimage without generating the calibration-use image including particulardistance information.

Next, processing for allocating a function of operation associated withthe image 113 to the operation switch 124 and processing for projectingoperation function information 122 corresponding to the allocatedfunction are explained. As the operation information associated with theimage 113, information for designating a large number of items to be setsuch as a projection position of the image 113, a size of an image to beprojected, brightness, contrast, gamma characteristic, colortemperature, tone, sharpness, a horizontal position, a verticalposition, a help, setting of a projection language, setting of aprojection time, a menu, a selection switch, or a power source switchcan be named.

A large number of operation switches 124 can be provided correspondingto the large number of items to be set. However, in performing a settingwork, operability for the user is further enhanced when only necessaryoperation switches 124 are made effective.

Here, functions allocated to the operation switch 124 can be varied and,at the same time, the operation function information 122 on theoperation switch 124 is projected in the vicinity of the operationswitch 124 in order to inform the user of the operation functioninformation 122.

The user can operate the operation switch 124 while looking at theprojected operation function information 122 and hence, a large numberof functions can be allocated to a small number of operation switches124 thus reducing a cost of the image display device 110.

The explanation is made with respect to processing, in allocatingvarious functions to the operation switches 124, for projecting theoperation function information 122 corresponding to the allocatedfunctions in conjunction with flowcharts shown in FIG. 38, FIG. 43 andFIG. 45.

FIG. 38 is a flowchart for executing menu projection processing. Whenthe image display device 110 shown in FIG. 28 is started, the processingexecuted by the information processing unit 180 advances to step S1102“read operation function information”. In S1102, the informationprocessing unit 180 reads data (KG0) for projecting the operationfunction information in an initial state from an ROM 183, generatesinformation including operation function information which correspondsto the video signal, and substitutes the generated information for theoperation function information (KG). In next step S1104 “projectoperation function information”, the information processing unit 180outputs the operation function information (KG) to the projection driver164 and, at the same time, outputs an instruction to the projectiondriver 164 to perform the synthesized projection.

The projection driver 164 synthesizes the operation function information(KG) acquired from the information processing unit 180 to the videosignal such as the RGB signal acquired from the computer device 800 inthe vicinity of the operation switch 124 or replaces the operationfunction information (KG) with the video signal, and outputs a drivesignal to the light modulation unit 162. Then, the projection part 165projects the projection light 112 generated by synthesizing theoperation function information (KG) to the video signal such as the RGBsignal acquired by the computer device 800 in the vicinity of theoperation switch 124. FIG. 39 shows a projection example of theoperation function information (KG=KG0).

In the projection example of the operation function information (KG=KG0)shown in FIG. 39, a state in which a function of projecting “menu” onsetting of the image 113 is allocated to the operation switch 124A isdescribed. Accordingly, in the vicinity of the operation switch 124A,“menu” is projected as the operation function information 122A. Nofunctions are allocated to operation switches 124B, 124C and hence,neither operation function information 122B nor 122C is displayed. Here,the switch identification display for showing the presence of theoperation switch 124A may be performed only at the operation switch 124Ato which the function is allocated.

In next step S1106 “menu button switch operated?”, the informationprocessing unit 180 executes processing for waiting an operation by auser of the operation switch 124A to which a function of a menu buttonswitch is allocated. When the user operates the operation switch 124A,the information processing unit 180 reads the information that theoperation switch 124A is operated via a received light informationprocessing unit 178 or an input interface 171. Then, the processingexecuted by the information processing unit 180 advances to next S1108“read menu image”.

In step S1108, the information processing unit 180 reads data (MG1) fordisplaying “menu” on setting of the image 113 from the ROM 183,generates information including the menu which corresponds to the videosignal, and stores the generated information in the RAM 181.

In next step S1110 “set inverted projection object”, the informationprocessing unit 180 reads an item (HG1) “the inverted projection object”for instructing the items to beset, and stores the read item in the RAM181 as an inverted projection object (HG).

In next step S1112 “read operation function information”, theinformation processing unit 180 reads data (KG1) for projectingoperation function information at the time of projecting the menu imagefrom the ROM 183, generates information including operation functioninformation which corresponds to the video signal, substitutes thegenerated information for the operation function information (KG), andstores the information in the RAM 181.

In next step S1114 “project menu”, the information processing unit 180designates and outputs the menu image (MG) and an inverted projectionobject (HG) in the menu image (MG) to the projection driver 164 and atthe same time, outputs the instruction of synthesized projection.

The projection driver 164 synthesizes menu image (MG) acquired from theinformation processing unit 180 and the inverted projection object (HG)of the menu image (MG) to the video signal such as the RGB signalacquired from the computer device 800 or replaces the menu image (MG)with the video signal, and outputs a drive signal to the lightmodulation unit 162. Then, the projection part 165 synthesizes andreplaces the menu image (MG) with the video signals such as the RGBsignals acquired from the computer device 800 and, at the same time,performs inverted projection processing such as projection usingcomplementary color with respect to an inverted projection object (HG)in the menu image. FIG. 40 shows a projection example of the menu image(MG=MG1) and the inverted projection object (HG) of the menu image.

Next, the explanation is made with respect to the projection example ofthe operation function information in a state that the menu image (MG)is projected.

In next step S1116 “project operation function information”, theinformation processing unit 180 outputs operation function information(KG) to the projection driver 164 and, at the same time, outputs aninstruction of synthesized projection. The projection driver 164synthesizes the menu image (MG) with the video signal such as the RGBsignal acquired from the computer device 800 or replaces the menu image(MG) with the video signal, and designates the inverted projectionobject (HG) of the menu image. Further, the projection driver 164synthesizes the operation function information (KG) to the vicinity ofthe operation switch 124 or replaces the operation function information(KG) with the operation function information (KG), and outputs a drivesignal to the light modulation unit 162.

Then, the projection part 165 synthesizes the menu image (MG) with thevideo signals such as the RGB signals acquired from the computer device800 or replaces the menu image (MG) with the video signal, and performsinverted projection processing such as projection using complementarycolor to the inverted projection object (HG) of the menu image. At thesame time, the projection part 165 projects the projection light 112generated by synthesizing the operation function information (KG) withthe video signal in the vicinity of the operation switch 124. FIG. 41shows a projection example of the operation function information(KG=KG1) projected together with the menu image (MG=MG1) shown in FIG.40.

As shown in FIG. 41, a function which allows the inverted projectionobject information (HG) to move to the next item is allocated to theoperation switch 124A and hence, “next item” is projected as theoperation function information 122A. In FIG. 41, for example, althoughthe item “change projection position” is inversely projected (in FIG.40, the item is projected in a meshed manner), when the user operatesthe operation switch 124A, the inverted projection moves to theprojected item “change image size” projected below the operation switch124A.

On the other hand, a function of selecting the item “inverted projectionobject information (HG)” is allocated to the operation switch 124B andhence, an operation switch 124B projects “selection” as operationfunction information 122B. When the user operates the operation switch124B in a state shown in FIG. 41, processing of the inversely projecteditem “change projection position” is selected, and the user can changethe projection position.

On the other hand, a function of canceling an operation on setting ofthe image 113 is allocated to the operation switch 124C and hence,“cancel” is projected as the operation function information 122C. Whenthe user operates the operation switch 124C in a state shown in FIG. 41,the projection of the menu image (MG) shown in FIG. 40 is canceled and,at the same time, processing for making the projection of the operationfunction information (KG) return to a content shown in FIG. 39 isexecuted. These processing are executed by carrying out steps S1118 toS1126 shown in FIG. 38, and the explanation of these steps is madeherein after.

In step S1118 “next item button switch operated?”, the informationprocessing unit 180 determines whether or not the operation switch 124Ato which the function which allows the inverted projection objectinformation (HG) to move to next item is allocated is operated by theuser. When it is determined that the operation switch 124A is operatedby the user, the processing which is executed by the informationprocessing unit 180 is branched to step S1120 “shift in the direction atwhich inverted projection object is designated”. Further, in step S1118,when it is determined that the operation switch 124A is not operated bythe user, the processing advances to a determination step S1122 “cancelbutton switch operated?”.

In step S1120, the information processing unit 180 reads the next itemof the inverted projection object (HG2) for instructing a setting item,and stores the read item to the RAM 181 as the inverted projectionobject (HG). The processing returns to step S1114, and the informationprocessing unit 180 instructs the projection driver 164 to perform theprojection of menu and the projection of operation function information.Then, the menu image (MG=MG1) shown in FIG. 42 and inverted projectionobject information (HG=HG2) of the menu image are projected.

On the other hand, in step S1122, the information processing unit 180determines whether or not a cancel button switch is operated. When it isdetermined that the cancel button switch is operated, the processing isbranched to step S1124 “cancel menu projection”. When it is determinedthat the cancel button switch is not operated, the processing advancesto the determination step S1126 “selection button switch operated?”.

In step S1124, the information processing unit 180 instructs theprojection driver 164 to cancel the projection of the menu image (MG)projected in step S1114. Then, the projection driver 164 projects theprojection light 112 generated by synthesizing only the operationfunction information (KG) with the video signal such as the RGB signalacquired from the computer device 800. When the processing in step S1124is finished, the processing executed by the information processing unit180 returns to S1102, and the projection driver 164 performs theprojection of the operation function information (KG=KG0) in an initialstate.

On the other hand, in step S1126, the information processing unit 180determines whether or not the selection button switch is operated. Whenit is determined that the selection button switch is operated, theprocessing is branched to step S1202 “read inverted information” shownin FIG. 43. When it is determined that the selection button switch isnot operated, the processing returns to step S1118, and waits inputtingby the user.

Next, the processing executed when the selection button switch isoperated is explained in conjunction with FIG. 43. In an example shownin FIG. 41, a function of a selection button switch is allocated to theoperation switch 124B.

In step S1202, the information processing unit 180 executes processingfor reading the currently inverted object information (HG) from the RAM181 and, at the same time, executes processing for reading informationon the presence or the non-presence of additional menu associated withthe currently inverted object (HG), or information on the presence orthe non-presence of setting-use projection from the ROM 183. Then, theprocessing advances to the next determination step S1204 “additionalmenu present?”.

In step S1204, the information processing unit determines whether or notthe additional menu associated with selected inverted object informationis present based on the information read in step S1202. When it isdetermined that the additional menu associated with the selectedinverted object information is present, the processing is branched tostep S1206 “read additional menu image”, and the lower hierarchicalprocessing is executed, that is, projection processing of the menu imageis executed. When it is determined that the additional menu is notpresent, the processing advances to the next determination step S1210“setting-use projection?”.

In step S1206, the information processing unit 180 reads data (MG2) fordisplaying “additional menu” on setting of the image 113 from the ROM183, generates information including a menu which corresponds to thevideo signal, and stores the generated information in the RAM 181.

In next step S1208 “set inverted projection object”, the informationprocessing unit 180 reads an item of the inverted projection object(HG3) of the additional menu for instructing the setting item from theROM 183, and stores the read item in the RAM 181 as the invertedprojection object (HG). Thereafter, the processing returns to S1114shown in FIG. 38, and the information processing unit 180 designates andoutputs the additional menu image (MG) and the inverted projectionobject (HG) of the additional menu image (MG) to the projection driver164 and, at the same time, instructs the projection driver 164 toperform the synthesized projection. FIG. 44 shows a projection exampleof the additional menu image (MG) projected in this manner.

In the embodiment shown in FIG. 44, as the additional menu of thesetting item “change image size”, two kinds of items “manually changeimage size” and “automatically change image size” are projected, whereinthe item “manually change image size” is inversely projected (in FIG.44, the item is projected in a meshed manner).

On the other hand, in step S1210, the information processing unitdetermines whether or not the selected inverted object information isprojected for setting based on the information read in step S1202. Whenit is determined that the inverted object information is projected forsetting, the processing is branched to step S1212 “cancel menuprojection”. When it is determined that the inverted object informationis not projected for setting, the processing advances to the nextdetermination step S1220 “power source OFF?”.

In step S1212, the information processing unit 180 instructs theprojection driver 164 to cancel the projection of the menu image (MG)projected in step S1114. Then, the projection driver 164 projects theprojection light 112 generated by synthesizing only the operationfunction information (KG) with the video signals such as the RGB signalsacquired from the computer device 800. When the processing in S1212 isfinished, the processing advances to next step S1214 “read setting-useimage”.

In step S1214, the information processing unit 180 reads data (SG1) fordisplaying “setting-use image” on setting of the image 113 from the ROM183, generates information of the set image (SG) corresponding to asetting-use video signal, and stores the generated information in theRAM 181.

In next step S1216 “read setting-use operation function information”,the information processing unit 180 reads data (KG2) for projectingoperation function information at the time of projecting the set imagefrom the ROM 183, generates information including operation functioninformation which corresponds to the video signal, substitutes thegenerated information for the operation function information (KG), andstores the information in the RAM 181.

In next step S1218 “store original volume value”, the informationprocessing unit 180 executes the processing for storing an originalvolume value (VR0) before setting in the RAM 181. The original volumevalue is a value which is explained herein after, for example.

When the user selects “change image size” in the setting menu forchanging the image size, a set value of the image size before changingsubstitutes for a volume value (VR0). When storing processing of theoriginal volume value (VR0) is finished, the processing advances to stepS1302 “project set image” shown in FIG. 45.

FIG. 45 is a flowchart for explaining processing for projecting an imagefor setting a projection position of the image 113, an image size,brightness and the like.

In step S1302, the information processing unit 180 reads the setting-useimage (SG) stored in the RAM 181 in S1214 and outputs the readsetting-use image to the projection driver 164 and, at the same time,instructs the projection driver 164 to perform the synthesizedprojection.

The projection driver 164 synthesizes the set image (SG) acquired fromthe information processing unit 180 with the video signal such as theRGB signal acquired from the computer device 800 or replaces the setimage (SG) with the video signal, and outputs a drive signal to thelight modulation unit 162. Then, the projection part 165 projects theprojection light 112 generated by synthesizing the set image (SG) withthe video signal such as the RGB signal acquired from the computerdevice 800 or replacing the set image (SG) with the video signal.

FIG. 46 shows a projection example of the set image (SG). FIG. 46 showsa projection example of the set image (SG) used for manually changing animage size. The example shown in FIG. 46 shows a state that, as a setvalue of the original image size before change, the volume value (VR0)of 50% is set, and five volume displays indicative of the volume valueof 50% are performed.

Next, the explanation is made with respect to a projection example ofthe operation function information in a state that the setting-use image(SG) is projected.

In S1304 “project operation function information” shown in FIG. 45, theinformation processing unit 180 reads the operation function information(KG) stored in the RAM 181 in step S1216 and outputs the readinformation to the projection driver 164 and, at the same time,instructs the projection driver 164 to perform the synthesizedprojection.

The projection driver 164 synthesizes the operation function information(KG) with the video signal such as the RGB signal acquired from thecomputer device 800 in the vicinity of the operation switch 124 orreplaces the operation function information (KG) with the video signal,and outputs a drive signal to the light modulation unit 162. Then, theprojection part 165 projects the projection light 112 generated bysynthesizing the menu image (MG) with the video signal such as the RGBsignal acquired from the computer device 800 or replacing the menu image(MG) with the video signal, and synthesizing the operation functioninformation (KG) with the video signal in the vicinity of the operationswitch 124. FIG. 47 shows a projection example of operation functioninformation (KG=KG2) projected together with the set image (SG=SG1)shown in FIG. 46.

As shown in FIG. 47, a function which allows the volume display to moveis allocated to the operation switch 124A and hence, “move volume” isprojected as the operation function information 122A. When the useroperates the operation switch 124A in a state shown in FIG. 46 that theset image (SG) is projected, for example, the volume display is movedand, at the same time, the volume value (VR1) of 60% can be set as shownin FIG. 48. These processing are executed by carrying out steps S1308 toS1310 shown in FIG. 45.

Further, in an example shown in FIG. 47, a function of fixing a volumevalue at a currently-set volume value is allocated to the operationswitch 124B and hence, “fixing” is projected as the operation functioninformation 122B. When the user operates the operation switch 124B in astate shown in FIG. 47, the volume value which is currently projected isdetermined, and the value is set as the volume value. These processingare executed by carrying out steps S1314 to S1316 shown in FIG. 45.

Further, a function of cancelling the operation on setting of the image113 is allocated to the operation switch 124C and hence, “cancel” isprojected as the operation function information 122C. When the useroperates the operation switch 124C in a state shown in FIG. 47, thevolume value which is currently projected is canceled, and theprocessing for making the volume value return to the original volumevalue shown in FIG. 46 is executed. These processing are executed bycarrying out steps S1320 to S1322 shown in FIG. 45.

Hereinafter, the explanation is made with respect to the processingexecuted when the operation switches 124A to 124C are operated by theuser.

In step S1306 “volume movement button switch operated?” shown in FIG.45, the information processing unit 180 determines whether or not theoperation switch 124A to which a function of changing the volume value(VR) is allocated is operated by the user. When it is determined thatthe operation switch 124A is operated by the user, the processing whichis executed by the information processing unit 180 is branched to stepS1308 “change volume value”. Further, when it is determined that theoperation switch 124A is not operated by the user in step S1306, theprocessing advances to a determination step S1312 “fixing button switchoperated?”.

In step S1308, the information processing unit 180 reads the currentvolume value (VR) from the RAM 181, executes processing for adding apredetermined volume value to the current volume value (VR) orsubtracting a predetermined volume value from the current volume value(VR), and executes processing for storing the acquired value as a newvolume value in the RAM 181.

Then, in the next step S1310 “shift volume display in the designateddirection”, the information processing unit 180 generates a video signal(SG2) for shifting the volume display in the designated direction, andinstructs the projection driver 164 to project the video signal (SG2) asthe set image (SG). Then, the set image (SG=SG2) shown in FIG. 48 isprojected. The example shown in FIG. 48 shows a state that, as a setvalue of the image size after change, the volume value (VR) of 60% isset, and six volume displays indicative of the volume value of 60% areperformed.

On the other hand, in step S1312, the information processing unit 180determines whether or not the fixing button switch is operated. When itis determined that the fixing button switch is operated, the processingis branched to step S1314 “fix volume value”. When it is determined thatthe fixing button switch is not operated in step S1312, the processingadvances to the next determination step S1318 “cancel button switchoperated?”.

In step S1314, the information processing unit 180 executes theprocessing which fixes the volume value (VR) to the currently-set volumevalue, and changes the setting of the image 113. When the image size ismanually changed, for example, the information processing unit 180executes the processing for outputting the instruction for changing theimage size to a currently-set image size corresponding to the volumevalue (VR) to the projection driver 164.

In next step S1316 “delete set image and operation functioninformation”, the information processing unit 180 instructs theprojection driver 164 to cancel the projection of the setting-use image(SG) and the operation function information (KG) projected in step S1302and step S1304. Then, the projection driver 164 projects the projectionlight 112 generated using the video signal such as the RGB signalacquired from the computer device 800. When the processing in step S1316is finished, the processing returns to step S1108 shown in FIG. 38, andprojects the menu image (MG) and the operation function information (KG)corresponding to the menu image (MG).

On the other hand, in step S1318, the information processing unit 180determines whether or not the cancel button switch is operated. When itis determined that the cancel button switch is operated, the processingis branched to step S1320 “return volume value to the original value andfix the volume value”. When it is determined that the cancel buttonswitch is not operated, the processing returns to S1306, and executesprocessing for waiting the selection button switch to be operated by theuser.

In step S1320, the information processing unit 180 executes theprocessing which cancels the currently-set volume value (VR), reads theoriginal volume value (VR0) stored in the RAM 181 and fixes the volumevalue, and returns the setting of the image 113 to the original setting.When the image size is manually changed, for example, the informationprocessing unit 180 outputs the instruction for returning the image sizeto the original image size before setting corresponding to the volumevalue (VR0) to the projection driver 164.

In next step S1322, the information processing unit 180 instructs theprojection driver 164 to cancel the projection of the setting-use image(SG) and the operation function information (KG) projected in S1302 andS1304. Then, the projection driver 164 projects the projection light 112generated using the video signal such as the RGB signal acquired fromthe computer device 800. When the processing in S1316 is finished, theprocessing returns to S1108 shown in FIG. 38, and projects the menuimage (MG) and the operation function information (KG) corresponding tothe menu image (MG).

By making a function allocated to the operation switch 124 variable and,at the same time, by projecting the operation function information 122of the operation switch 124 in the vicinity of the operation switch 124as described above, it is possible to easily set a projection positionof the image 113, a size of the image to be projected, brightness,contrast, gamma, color temperature, tone, sharpness, a horizontalposition, a vertical position, projection of a help-image, setting of aprojection language, setting of a projection time, projection of amenu-image, a selection switch, a power source switch or the like.

Next+, a varying mechanism capable of changing a height of theprojection part in the image display device is explained.

FIG. 49 shows an embodiment of an image display device 210 whichincludes a varying mechanism capable of changing the height of theprojection part 114 relative to a pedestal 218 in place of the supportcolumn 116 of the image display device 110 shown in FIG. 28.

As shown in FIG. 49, the projection part 114 of the image display device210 receives inputting of a video signal such as an RGB signal from acomputer device, generates a projection light 112 based on the inputtedvideo signal, and projects the projection light to a table.

In this manner, in the image display device 210 of this embodiment, theprojection part 114 is vertically movably mounted on the pedestal 218 inan erected manner using a pantograph-type varying mechanism 216.Accordingly the height of the projection part 114 can be changed andhence, the height of the projection part 114 relative to the pedestal218 is lowered at the time of housing the image display device 210 sothat the image display device 210 can be housed in a compact manner.

Further, as shown in FIG. 49, with the provision of the varyingmechanism capable of changing the height of the projection part 114relative to the pedestal 218, it is possible to adjust a size of theimage 113 to be projected. Here, as a varying mechanism which changesthe height of the projection part 114 relative to the pedestal 218, aslide-type varying mechanism, an arm-type varying mechanism or the likecan be used.

Further, by forming a projection region 119 where a portion of the image113 can be formed by the projection light 112 on the pedestal 218, it ispossible to mount the projection part 114 in an erected manner at aposition closer to the center of gravity of the pedestal 218.Accordingly, the stability of the image display device 210 when theimage display device 210 is mounted on a table is increased. Further, aprojection angle of the projection light 112 is made to approximate aright angle and hence, the image display device 210 can form an imagewith small distortion.

FIG. 50 is a view showing an embodiment of an image display device 310having a mechanism for storing the screen 340 on the pedestal 118 of theimage display device 110 shown in FIG. 28.

As shown in FIG. 50, a projection region 119 where a portion of an imagecan be formed by the projection light 112 is formed on the pedestal 318of the image display device 310 and, at the same time, the pedestal 318includes a winding-type storage mechanism 342 for storing the screen 340in the inside thereof.

In this manner, the image display device 210 of this embodiment includesthe winding-type storage mechanism 342 for storing the screen 340 in theinside of the pedestal 318 and hence, it is possible to store the screen340 in the inside of the pedestal 318 in a compact manner. A positionwhere the winding-type storage mechanism 342 is arranged is not limitedto a lower portion of the projection region 119 as shown in FIG. 50.Here, by arranging the winding-type storage mechanism 342 below theprojection region 119 or a photo detector in an overlapping manner, itis possible to make the pedestal 318 small-sized.

Further, by forming the projection region 119 on a portion of thepedestal 118, it is possible to mount the projection part 114 in anerected manner at a position closer to the center of gravity of apedestal 318 and hence, stability of the image display device 310 whenthe image display device 310 is mounted on a table is increased.Further, it is possible to make the radiation angle of the projectionlight 112 to approximate a right angle and hence, the image with smalldistortion can be formed. Here, the storage mechanism of the screen 340can be used in combination with a varying mechanism such as thepantograph-type varying mechanism 216 shown in FIG. 49.

FIG. 51 is a view showing an embodiment of an image display device 410which is formed by mounting a stabilizing member for preventing fallingof the image display device 410 on the pedestal 318 having a mechanismfor storing a screen 340.

As shown in FIG. 51, the pedestal 418 of the image display device 410includes a winding-type storage mechanism 342 for storing the screen 340in the inside of the pedestal 418 and a pantograph type stabilizingmember 444 for preventing the image display device 410 from falling thusincreasing stability of the image display device 410 in use. By formingthe pantograph-type stabilizing member 444 on a portion of the pedestal418, it is possible to increase stability of the image display device410 in use and, at the same time, the image display device 410 can bestored in a compact manner.

A position where the winding-type storage mechanism 342 is arranged anda position where the pantograph type stabilizing member 444 is arrangedare not limited to positions below the projection region 119 shown inFIG. 51. However, by arranging the storing portion for storing thewinding-type storage mechanism 342 and the pantograph type stabilizingmember 444 below the projection region 119 or below the photo detectorin an overlapping manner, the pedestal 418 can be miniaturized. Here,the storing portion for storing the pantograph type stabilizing member444 may be arranged below the winding-type storage mechanism 342 in anoverlapping manner.

FIG. 52 is a view showing an embodiment of an image display device 510which is formed by mounting a stabilizing member for preventing fallingon a pedestal 118 of the image display device 110 shown in FIG. 28.

As shown in FIG. 52, the pedestal 518 of the image display device 510includes a storable storing stabilizing member 546 for enhancing thestability of the image display device 510 in use thus preventing thefalling of the image display device 510. By forming the storablestabilizing member 546 on the projection region of the pedestal 518, itis possible to store the image display device 510 in a compact mannerwhile enhancing the stability of the image display device 510 in use.Further, in the inside of the pedestal 518, the winding-type storagemechanism 342 shown in FIG. 50 may be arranged in parallel.

In the example shown in FIG. 52, the stabilizing member 546 which isstorable in the direction toward the center is mounted on both endportions of the pedestal 518. However, the mounting of the storablestabilizing member 546 is not limited to such a configuration and thestorable stabilizing member 546 may be mounted on the center portion ofthe pedestal 518.

Fourth Embodiment

FIG. 53 is a view showing an embodiment of an image display device 610which further enhances the stability of the image display device 610 byforming a fixed-type screen 640 to the pedestal portion of the imagedisplay device 110 shown in FIG. 28.

The image display device 610 includes a projection part 114 whichgenerates projection light 112 in response to a video signal andprojects an image on a screen 640, a support column 116 which supportsthe projection part 114, and a pedestal 618 which mounts the projectionpart 114 and the support column 116 thereon in an erected manner. Theimage display device 610 receives inputting of video signals such as RGBsignal from a computer device not shown in the drawing, generates theprojection light 112 based on the inputted video signal, and radiatesthe projection light 112 to the screen 640 mounted on the pedestal 618.By mounting the screen 640 which constitutes the projection region forforming the image 113 by the projection light 112, it is possible tomake the radiate projection light 112 approximate a right angle.Accordingly, the image display device 610 can display the easilyviewable image 113 with small distortion.

Further, by mounting the screen 640 on the pedestal 618, it is possibleto ensure a large pedestal installation area on an image side.Accordingly, the projection part 114 and the support column 116 can bemounted in an erected manner close to the center of gravity of thepedestal 618 and hence, the image display device 610 can increasestability thereof when placed on a table thus preventing the falling ofthe image display device 610.

Further, as shown in FIG. 53, when a user performs an operation relatingto the image 113, it is possible to mount the photo detector 126 on thepedestal 618 as an operation switch 124. In a state that the photodetector 126 is used as the operation switch 124, when the user extendshis/her finger to a position above the photo detector 126 to blockprojection light 112 which the photo detector 126 receives, receivedlight information which the photo detector 126 outputs is changed andhence, the image display device 610 can detect that the photo detector126 is operated by the user.

Further, image display device 610 displays operation functioninformation 122 which informs a user of a function allocated to theoperation switch 124 on a portion of the image 113 thus enhancing theeasy-to-use property enjoyed by the user. Further, to show the presenceof the operation switch 124, a switch identification display whichidentifies a range of the operation switch 124 and a periphery of therange may be performed in a portion of the image 113. The switchidentification display may be a display having complementary color ormaking high contrast against a background. Further, when a photodetector 126 is used as the operation switch 124, in the switchidentification display, light having a wavelength which is not includedin light having high brightness such as white light or a fluorescentlamp may preferably be projected.

The function and the manner of operation of the operation switch 124 areequal to the function and the manner of operation explained inconjunction with FIG. 28 and hence, the explanation of the function andthe manner of operation of the operation switch 124 is omitted here. Theoperation switch 124 may be arranged outside the image 113. Further, inplace of using the photo detector 126 as the operation switch 124, aninput unit 170 (see FIG. 31) which is constituted of a push buttonswitch or the like may be used.

FIG. 54 shows an embodiment of an image display device 710 provided witha foldable screen 740 on the pedestal 618 in the image display device610 shown in FIG. 53.

As shown in FIG. 54, the image display device 710 mounts a screen on apedestal 718 thereof, and includes a mechanism 748 such as a hinge whichmakes the screen 740 foldable. By providing the foldable screen 740 tothe pedestal 718, the image display device 710 can easily store to imagedisplay device 710 while maintaining an image of high quality.

Further, the image display device 710 may be configured such that whenthe screen 740 is folded, the mechanical operation switch 124 is pusheddown or when the screen 740 is folded, light received by the operationswitch 124 constituted of the photo detector 126 is blocked so that upondetection of a state that the operation switch 124 is pushed down or astate that the light received by the operation switch 124 of the photodetector 126 is blocked, the supply of electricity to the image displaydevice 710 is cut off. Further, upon detection of a state that themechanical operation switch 124 is released or a state that the photodetector 126 receives light, electricity is supplied to the imagedisplay device 710. Due to such a constitution, by merely folding thescreen 740, it is possible to automatically supply electricity to theimage display device 710 or to cut off the supply of electricity to theimage display device 710.

In the embodiment explained in conjunction with FIG. 54, the foldablemechanism 748 is provided at a portion of the center of the screen 740and the folding-side screen 740 is foldable in the direction K so as tocover the operation switch 124. However, the folding-side screen 740 maybe folded in the direction L opposite to the direction K. Further, thefoldable mechanism 748 may be provided at a plurality of positions suchthat the screen can be folded like bellows thus enabling the storing ofthe image display device 710 in a compact shape.

Although the preferred embodiments of the present invention have beenexplained heretofore, the present invention is not limited to suchspecific embodiments and various modifications and variations areconceivable without departing from the gist of the present invention.

1. An image display device for projecting light on a projection surfaceto display an image on the projection surface, the image display devicecomprising: at least one processor; an aptitude detection partconfigured to detect an aptitude as the projection surface; and memorystoring computer-readable instructions that, when executed, cause the atleast one processor to function as: a projection control unit configuredto control the projection light to allow the image to be displayed onthe projection surface to fall within a predetermined projection regionin response to a result of detection by the aptitude detection part; anda region selection part configured to select the projection region inresponse to the result of detection by the aptitude detection part,wherein the aptitude detection part is configured to detect, in a statewhere the projection region is formed of a mass of a plurality ofdivided regions, an aptitude value as the projection surface in eachdivided region, wherein the region selection part is configured toselect, based on the aptitude values, one or more divided regions fromthe plurality of divided regions as the projection region, and whereinthe projection control unit is configured to control the projectionlight to allow the image to be displayed on the projection surface tofall within the selected projection region, wherein the aptitudedetection part is configured to detect, based on reflection waves of anelectromagnetic wave or an ultrasonic wave radiated toward each dividedregion, at least one of a position of a reflection point of theelectromagnetic wave or the ultrasonic wave and a surface shape of areflection surface including the reflection point, and the aptitudedetection part is configured to detect, based on at least the positionof the reflection point or the surface shape of the reflection surface,the aptitude value of the corresponding divided region, wherein theaptitude detection part is configured to treat the projection region asa mass of three or more divided regions and is configured to detect theaptitude value based on at least the position of the reflection point,is configured to set positions determined based on the positions of oneor more reflection points within the divided region as evaluation-usepositions in the corresponding divided region, is configured to selectthree or more divided regions, and when the evaluation-use positions inthe three or more selected divided regions are on one plane, isconfigured to detect the aptitude values determined as projectioncandidate regions with respect to three or more selected dividedregions.
 2. An image display device according to claim 1, wherein theregion selection part is configured to determine one or more dividedregions of the plurality of divided regions as projection candidateregions based on the aptitude values, and is configured to select one ormore projection candidate regions as the projection region from theplurality of projection candidate regions based on positions orarrangements of the projection candidate regions within the projectionregion.
 3. An image display device according to claim 1, wherein theaptitude detection part is configured to use the position of onereflection point within the divided region as the evaluation-useposition, and is configured to select three or more divided regions outof the divided regions where the radiation directions of theelectromagnetic waves or the ultrasonic waves incident on the reflectionpoints used as the evaluation-use positions are on the same plane, andwhen the positions of the reflection points used as the evaluation-usepositions in three or more selected divided regions are on one straightline, the aptitude detection part is configured to detect the aptitudevalues determined as projection candidate regions in three or moreselected divided regions.
 4. An image display device according to claim1, wherein the aptitude detection part is configured to detect, based onreflection light of white light projected toward at least the respectivedivided regions, colors of the divided regions, and is configured todetects the aptitude values of the divided regions corresponding to thecolors.
 5. An image display device according to claim 1, wherein theaptitude detection part is configured to detect, based on reflectionlight of white light projected toward at least the respective dividedregions, brightnesses of the divided regions, and is configured todetect the aptitude values of the divided regions corresponding to thebrightnesses.
 6. An image display device according to claim 2, whereinthe region selection part, when the divided region including a centerposition of the projection area is included as one of the projectioncandidate regions, is configured to select the divided region includingthe center position to be part of the projection region.
 7. An imagedisplay device according to claim 2, wherein the region selection part,when a maximum similar shape which falls within one or more projectioncandidate regions out of similar shapes similar to a shape of aprojection range of the projection light overlaps with one or moreprojection candidate regions, is configured to select one or moreprojection candidate regions which overlap with the similar shape to bepart of the projection region.
 8. An image display device for projectinglight on a projection surface to display an image on the projectionsurface, the image display device comprising: at least one processor; anaptitude detection part configured to detect an aptitude as theprojection surface; a projection part configured to generate and projectprojection light based on a video signal; a pedestal which mounts theprojection part in an erected manner, wherein the projection part isconfigured to project the projection light such that at least a portionof the projection light is radiated to the pedestal; a projection spacewhere at least a portion of an image formed by the projection light isformed on the pedestal; and memory storing computer-readableinstructions that, when executed, cause the at least one processor tofunction as: a projection control unit configured to control theprojection light to allow the image to be displayed on the projectionsurface to fall within a predetermined projection region in response toa result of detection by the aptitude detection part; and a regionselection part configured to select the projection region in response tothe result of detection by the aptitude detection part, wherein theaptitude detection part is configured to detect, in a state where theprojection region is formed of a mass of a plurality of divided regions,an aptitude value as the projection surface in each divided region,wherein the region selection part is configured to select, based on theaptitude values, one or more divided regions from the plurality ofdivided regions as the projection region, wherein the projection controlunit is configured to control the projection light to allow the image tobe displayed on the projection surface to fall within the selectedprojection region, wherein the aptitude detection part includes a photodetector mounted in the projection space of the pedestal, and isconfigured to receive the projection light and is configured to outputreceived light information after converting received light into thereceived light information, and wherein the projection control unit isconfigured to change a size of the image or a projection position of theimage based on the received light information.
 9. An image displaydevice according to claim 8, wherein the memory stores additionalcomputer-readable instructions that, when executed, further cause the atleast one processor to function as a distance information generationunit configured to generate a video signal including distanceinformation of the image formed by the projection light corresponding toa distance from a projection end on the pedestal side, and is configuredto output the video signal to the projection part, and wherein theprojection control unit is configured to change the size of the image orthe projection position of the image based on the received lightinformation outputted by the photo detector and the distanceinformation.
 10. An image display device according to claim 9, whereinthe distance information generation unit is configured to generatedistance information expressing the distance of the image formed by theprojection light from the projection end on the pedestal side as thedifference in projection mode.
 11. An image display device according toclaim 10, wherein the distance information is the projection mode of theimage having different characteristics corresponding to the distancesfrom the projection end on the pedestal side.
 12. An image displaydevice according to claim 11, wherein the distance information includesa characteristic parallel to the projection end on the pedestal side.13. An image display device according to claim 11, wherein the distanceinformation is an image projected only in the vicinity of the photodetector.
 14. An image display device according to claim 11, wherein thedistance information is an image projected only within a range of apredetermined distance from the projection end on the pedestal end. 15.An image display device according to claim 8, wherein the image displaydevice includes an operation switch mounted on the pedestal and outputsoperation information when an operation relating to the image isperformed, and wherein the memory stores additional computer-readableinstructions that, when executed, further cause the at least oneprocessor to function as a function information generation unitconfigured to generate a video signal including operation functioninformation for projecting a function allocated to the operation switchand outputs the video signal on the projection part.
 16. An imagedisplay device according to claim 15, wherein the operation switch is aphoto detection switch configured to receive the projection light,convert the received light into the operation information, and outputthe operation information.
 17. An image display device according toclaim 8, wherein the image display device includes a varying mechanismcapable of changing a height of the projection part relative to thepedestal.
 18. An image display device according to claim 8, wherein thepedestal includes a storable or foldable screen.
 19. An image displaydevice for projecting light on a projection surface to display an imageon the projection surface, the image display device comprising: at leastone processor; an aptitude detection part configured to detect anaptitude as the projection surface; a projection part configured togenerate and project projection light based on a video signal; apedestal which mounts the projection part in an erected manner, whereinthe projection part is configured to project the projection light suchthat at least a portion of the projection light is radiated to thepedestal; a projection space where at least a portion of an image formedby the projection light is formed on the pedestal; and memory storingcomputer-readable instructions that, when executed, cause the at leastone processor to function as: a projection control unit configured tocontrol the projection light to allow the image to be displayed on theprojection surface to fall within a predetermined projection region inresponse to a result of detection by the aptitude detection part; and aregion selection part configured to select the projection region inresponse to the result of detection by the aptitude detection part,wherein the aptitude detection part is configured to detect, in a statewhere the projection region is formed of a mass of a plurality ofdivided regions, an aptitude value as the projection surface in eachdivided region, wherein the region selection part is configured toselect, based on the aptitude values, one or more divided regions fromthe plurality of divided regions as the projection region, wherein theprojection control unit is configured to control the projection light toallow the image to be displayed on the projection surface to fall withinthe selected projection region, and wherein the projection part isconfigured to project light at a projection angle θs larger than aninclination angle θd when a stepped portion of the acute inclinationangle θd is present in the projection region on the pedestal.